Complex formation analysis of water-soluble calixarenes by capillary zone electrophoresis

The equilibria of complex formation reactions between various kinds of cations and anionic calixarenes in an aqueous solution were analyzed by capillary zone electrophoresis on the basis of the change in electrophoretic mobility of the calixarenes. The apparent electrophoretic mobility of the calixarenes decreased with increasing concentrations of alkali metal ions and quaternary ammonium ions. Equilibrium constants were determined by a non-liner least-squares analysis using the changes in apparent electrophoretic mobility. The complex formation constants obtained with alkali metal ions were in the order of 10(2.3) - 10(3.0), and those with quaternary ammonium ions were 10(2.9) - 10(4.2), providing less selectivity among them. The selectivity of the calixarene toward alkali metal and quaternary ammonium ions in aqueous solution involves flexible structure, and compensative interactions of electrostatic and hydrophobic interactions. From the results obtained in this work, the electrophoretic method has proved to be useful for analyzing the reactivity of anionic calixarene in aqueous solution.

Separation and determination of n-alkylamines and histamine by capillary zone electrophoresis using salicylaldehyde-5-sulfonate as a derivatizing reagent

Sodium salicylaldehyde-5-sulfonate (SAS) was investigated as a derivatizing reagent for the separation and determination of primary amines by capillary zone electrophoresis (CZE). The amines were derivatized with SAS to the corresponding Schiff bases before their determination. Optimal conditions for the formation reactions of the Schiff bases and the CZE analysis were investigated in details. The Schiff bases were formed almost completely within 9 min in 40%(v/v) ethanol solution at 40 degrrees C. A migrating solution containing 40%(v/v) ethanol and 20 mM phosphate buffer (pH 7.8) was found to be preferable for the stability of the Schiff bases. Eight kinds of n-alkylamines were derivatized with SAS under the optimal conditions and the derivatives were successfully separated by a CZE analysis. The proposed method allows simultaneous, sensitive and sufficiently precise determination of the n-alkylamines with the alkyl chain length from 3 to 12 of methylene groups. The derivatization process with SAS was successfully applied to the detection of histamine at a very low level. The detection limit was 2.5-10(-6) M, and it was improved in the order of 8 times compared with the CZE analysis without derivatization.

Highly sensitive determination method for total carbonate in water samples by flow injection analysis coupled with gas-diffusion separation

A spectrophotometric method for the determination of total carbonate in water samples was developed. The method is based on the color change of an acid-base indicator in relation to the concentration of permeable gas substances through a membrane. By using a new portable FIA system equipped with a gas-diffusion unit, a highly sensitive and on-site determination of total carbonate in aqueous solutions was investigated. A new color-change system with 4-(2',4'-dinitrophenylazo)-1-naphthol-5-sulfonic acid (DNN5S) was developed. Absorbance changes of the reagent solution were measured at 450 nm with a light-emitting diode (LED) as a light source. A new type of gas-diffusion unit was used, and was constructed with double tubing: the inner tubing was a micro porous PTFE (polytetrafluoroethylene) tubing (1.0 mm inner diameter and 1.8 mm outer diameter, pore size 2 microns, porosity 50%); the outer tubing was made of glass with 2.0 mm inner diameter. The optimized system conditions were as follows: the sample size was 200 microliters, the temperature of the air bath for the gas-diffusion unit was 25 degrees C, and the length of the gas-diffusion unit was 15 cm; each flow rate was 0.3 ml min-1. For measuring carbonate at low concentrations, a method for preparing water with less carbonate was proposed: the carbonate content of the water was decreased down to 5 x 10(-7) M. The calibration graph was rectilinear from 1 x 10(-6) M to 10(-3) M, and the detection limit (corresponding to a signal-to-noise ratio of 3) was 1 x 10(-6) M of carbonate. The relative standard deviation (RSD) of ten measurements of 2.3 x 10(-5) M Na2CO3 solution was 1.9%. The total carbonate in various kinds of water (such as river, sea, rain, distilled and ultra purified) was determined.

Analysis of complex formation between crown ethers and potassium ion by determining retention factors in reversed-phase high-performance liquid chromatography

Retention factors in reversed-phase high-performance liquid chromatography (RP-HPLC) were utilized for the analysis of complex formation reaction of four crown ethers with potassium ion in water-methanol media. The crown ethers were injected as analytes, potassium ion was present in the eluent, and three types of reversed-phase columns were used. The retention factor of the crown ethers decreased with increasing concentrations of potassium ion in the eluent, which is attributed to the change in the species of the crown ether from a neutral ligand to a positively charged complex. The complex formation constants were determined by analyzing the changes in the retention factor with a non-linear least-squares method.

Severe cervical kyphosis in osteopathia striata with cranial sclerosis: case report

We report a 29-month-old girl with osteopathia striata with cranial sclerosis (OS-CS), who showed several unusual manifestations, including short stature, muscular hypotonia, short lingual frenulum, an accessory ear and a granuloma at the oral edge. The most unusual distressing finding was severe cervical kyphosis with a dysplastic cervical spine. MRI revealed impingement of the upper spinal cord. To clarify the mode of inheritance of this disease in this patient, we performed a methylation-specific PCR analysis. It eventually showed random inactivation of X-chromosomes, suggesting an autosomal dominant trait.

[Survey of consciousness of community residents regarding the community life of disabled persons with service dogs]

PURPOSE

Service dogs have received much attention as effective choices for promoting participation in society of disabled persons. The purpose of this study was to obtain the fundamental data to prepare guidelines regarding service dogs use in community life, by making clear the problems in terms of public health and community welfare through a survey of attitudes towards service dogs in community residents.

METHODS

Study 1 was conducted as follows. The subjects were 423 community residents between their teens and seventies who participated in health and welfare lectures in 4 metropolitan areas. A questionnaire survey was conducted just after watching a promotion video about service dogs, including several items on aspects not accept, were anxious about or were unpleasant in the case of community life of a disabled person and a service dog. Study 2 was as follows. A questionnaire survey was conducted inside a supermarket in the central part of Tokyo. One group of subjects were 103 shopping customers who witnessed a shopping scene featuring a disabled person with her service dog, and the other subjects were 84 customers who were not witnessed to the scene. The same survey was simultaneously performed for impression about the shopping scene.

RESULTS

Study 1 showed that 31.8% of all the respondents replied that they had some knowledge of service dogs before watching the video. A total of 20.4% (32.5% of the elderly) replied that there were places where service dogs should not enter. Concretely speaking, these included restaurants for 7.3-22.5% and medical institutions for 8.5-12.5% of the respondents. A third of all the respondents (51.3% of older persons) replied they could not endure some actions by service dogs, concretely "carrying food in the mouth" was highly pointed out by 27.3%. Zoonosis (15.3-19.0%), hair scattering (9.5-21.3%), injuries (4.4-7.4%) were also pointed out as main sources of anxiety or uncomfortable feelings. Such negative opinions were especially apparent among those aged 60 years and older. Also, 44.1% knew some disabled person. Cross tabulation showed those who had experience of taking care of a dog were significant less anxious about "vague anxiety or discomfort," and "zoonosis" than those who had not (P < 0.01). On the other hand, most of both witness (79.6%), and non-witness groups (81.0%) replied that it was heartwarming that the service dog assisted with shopping. None expressed discomfort about the presence of "service dog" inside the supermarket. In terms of carrying a commodity in the mouth, 92.2% and 89.1% in both groups replied that they don't mind, especially if safety was guaranteed for public health, and 91.3% and 95.2% in both groups replied that they had no other problems. Moreover, none of them would not entering stores. Significant differences were seldom in replies between the witness and non-witness groups.

CONCLUSION

Although the respondents were extremely affirmative regarding the image of service dogs, it became clear that anxiety about public health aspects such as "zoonosis" or "utilization of medical institutions" was persisting. On the whole, negative opinions were more apparent in the elderly.

Expression of constitutively active c-MET receptor in human choriocarcinoma

OBJECTIVE

The c-MET oncogene encodes the transmembrane tyrosine kinase receptor for hepatocyte growth factor (HGF). Recently, either HGF or c-MET has been knocked out in the mouse, and the mutation is associated with defects in the development of the placenta by means of the reduction of trophoblast cells. We examined the role of c-MET in malignant transformation of trophoblast cells.

METHODS

In four human choriocarcinoma cell lines, GCH-1, GCH-1m, NUC-1 and SCH, the expression of HGF and c-MET was analyzed by RT-PCR and Western blotting using anti-c-MET antibody and antiphosphotyrosine antibody.

RESULTS

RT-PCR analysis showed that no cell lines expressed HGF, however all the cell lines revealed the expression of c-MET mRNA. c-MET receptor was expressed and also tyrosine-phosphorylated constitutively in these cell lines by Western blotting.

CONCLUSION

These results suggest that c-MET may be involved in the growth and behavior of human choriocarcinoma although an autocrine fashion of HGF is unlikely.

Separation and determination of haloperidol, parabens and some of their degradation products by micellar electrokinetic chromatography

A micellar solution containing phosphate buffer, anionic surfactant, and water-miscible organic solvent was employed as a migration solution for the separation and the quantification of eleven analytes by micellar electrokinetic chromatography (MEKC): the analytes examined were haloperidol, methylparaben, ethylparaben, n-propylparaben, iso-propylparaben, n-butylparaben, iso-butylparaben, sec-butylparaben, 4-(4-chlorophenyl)-4-hydroxypiperidine, 4-fluorobenzoic acid and 4-hydroxybenzoic acid. In order to provide good separation between micelle and haloperidol, which showed strongest interaction with the micelle among the analytes, surfactant concentrations and organic modifier percentages were studied with phosphate buffer at pH 7.0. All the analytes were successfully resolved when 10 mM sodium dodecylsulfate and 15% ethanol were contained in the migration solution; the time window was very wide in the range from 14.8 to 65.5 min. Optimized applied voltage at 30 kV and capillary temperature at 45 degrees C enable analyze all compounds in less than 17 min with the best resolution, the shorter migration time window, the highest precision and lowest detection limit.

[A case of antiphospholipid antibody syndrome with cerebral infarction showing slowly progressive pure motor monoparesis in unilateral upper extremity]

We reported a 68-year-old man with anti-phospholipid antibody syndrome who presented slowly progressive pure motor monoparesis(PMM) in left upper extremity as a sign of cerebral infarction. He had history of hypertension and hyperlipidemia. He first noticed clumsiness in left fingers, then weakness of left fingers with drop hand developing gradually in 2 to 6 weeks. He began to feel difficulty in raising left upper arm in 8 weeks and was admitted to our hospital. On admission, he exhibited severe weakness in distal portion and moderate weakness in proximal portion of left upper extremity. Deep tendon reflexes were slightly hyperactive in left side. Muscle strength of right upper extremity and bilateral lower extremities were normal. There was no sensory and autonomic abnormality. Laboratory examination revealed high titer of anti-cardiolipin IgM antibody. Brain MRI demonstrated a small cortical infarction in the right precentral gyrus. Cerebral angiography revealed severe stenosis in right common carotid artery. Other examinations including EMG were unremarkable. PMM in left upper extremity was considered to be caused by the ischemic lesion in the precentral motor cortex. Slowly progressive course might be explained by the hypovolemic factor due to the marked stenosis in right common carotid artery, poor collateral circulation, and abnormal coagulation caused by anti-phospholipid antibody syndrome.

[A patient of Charcot-Marie-tooth disease with rigid spine and respiratory failure]

This report describes a case of a 17-year-old girl with Charcot-Marie-Tooth disease (CMT) representing rigid spine and respiratory failure. At age 11, she tended to walk on her toes and had difficulty in getting up from the floor without support. She became aware of flexion limitation of the neck at the age of 12. At 15 years of age, She began to have dyspnea on effort. When she was 17 years old, neurological examination revealed mild weakness of the upper extremities and severe weakness of the distal lower extremities, generalized wasting and areflexia. Superficial sensation was mildly impaired distally, and vibration sensation was severely impaired in the lower extremities. Motor and sensory nerve conduction velocities were mildly reduced, and compound muscle action potential of the tibial and peroneal nerves and sensory nerve action potential on ulnar and sural nerves were absent. Electromyography showed neurogenic changes with denervation potentials. Sural nerve biopsy revealed severe loss of myelinated fibers without any onion-bulb formation. As for family history, her elder sister showed moderate loss of vibration sensation in the lower extremities. On the basis of these findings, she was diagnosed as having CMT type 2, though a mode of inheritance was uncertain. She also had peculiar findings of flexion limitation of the spine (rigid spine), contracture of the hip joint, and fatty degeneration of paraspinal muscles on CT. Percent vital capacity (VC) was 22.5%, and arterial blood gas analysis showed PaO2 of 60.5 mmHg and PaCO2 65.0 mmHg. To our knowledge, this is the first case of CMT accompanied by rigid spine and respiratory failure. Motor and sensory neuropathy combined with rigid spine also have not been reported previously. The relationship between rigid spine syndrome with neurogenic muscular atrophy and CMT type 2C with the clinical characteristics of diaphragm and vocal cord paresis is discussed.

Drop in relapse rate of MS by combination therapy of three different phosphodiesterase inhibitors

Phosphodiesterase inhibitors (PDEIs), when used in combination, synergistically suppress TNFalpha production by various cells and also suppress experimental demyelination at very low concentrations. We conducted a pilot study to determine whether the combination of three PDEIs suppresses the relapse of MS at the usual therapeutic doses. Of the 12 relapsing remitting MS, the mean relapse rate/year dropped remarkably (from 3.08+/-3.32 to 0.92+/-1.86) after PDEI treatment. Seven out of 12 (58.3%) were relapse-free in the follow up period (499+/-142 days). The combination of three PDEIs can be safe and useful strategy for the future treatment of MS. - 58

[A case of Fisher syndrome showing pharyngeal-cervical-brachial weakness with an elevation of anti-GQ 1 b and anti-GT 1 a antibodies]

A 15-year-old boy developed ataxic gait, diplopia and hoarseness. Within 3 days after the onset, he had additional symptoms of dysphagia and dysarthria. He was admitted to our hospital 7 days after the onset of the disease. On admission, he had total ophthalmoplegia, ataxia, areflexia, facial diplegia, bulbar palsy and weakness of the neck and upper arms. Serum anti-GQ 1 b and anti-GT 1 a antibodies were significantly elevated. A diagnosis of Fisher syndrome associated with pharyngeal-cervical-brachial weakness was made. He was placed on a high dose of intravenous immunoglobins (12.5 g/day x 2 days) and had steroid pulse therapy (methylprednisolone 1 g x 3 days), which resulted in an almost complete recovery. There have been no reports of Fisher syndrome associated with brachio-pharyngeal-palsy. As in the case of the pharyngeal-cervical-brachial variant of Guillain Barré syndrome, anti-GT 1 a antibodies may be associated with Fisher syndrome with pharyngeal-cervical-brachial weakness.

Tetrodotoxin-sensitive persistent current boosts the depolarization of retinal amacrine cells in goldfish

To light illumination retinal amacrine cells respond with graded depolarization accompanied by a spike discharge. It has been assumed that the graded depolarization is produced solely by the excitatory synaptic inputs from bipolar cells. Here we demonstrate that a tetrodotoxin (TTX)-sensitive persistent current also contributes to the graded depolarization. This current was isolated in amacrine cells of the goldfish retinal slice preparations by the whole-cell patch clamp technique. The activation threshold of the persistent current was about -50 mV, approximately 10 mV more positive than the membrane potential in the dark. Therefore, it is highly likely that the TTX-sensitive persistent current is a booster of the excitatory postsynaptic potential in amacrine cells.

Delayed clearance of zymosan-induced granuloma and depressed phagocytosis of macrophages with concomitant up-regulated kinase activities of Src-family in a human monocyte chemoattractant protein-1 transgenic mouse

A human monocyte chemoattractant protein-1 (hMCP-1) transgenic mouse (Tgm) line which constitutively produces a large amount of hMCP-1 (7-13 ng/ml in the serum) was established. Although expression of the transgene was detected in various tissues, an accumulation of macrophages (Mphi) was seen in only lymphoid organs which might be attributed to the high concentration of hMCP-1 in these organs. A reduced phagocytosis by peritoneal Mphi in vivo and a delayed clearance of granulomas in the liver following zymosan administration were observed in these Tgm. However, peritoneal exudate cells (PEC) from Tgm exhibited normal in vitro phagocytic activity and nitric oxide (NO) production upon stimulation with IFN-gamma as compared with those from non-Tgm. In addition, high activities of src-family protein tyrosine kinases (PTK), Fgr and Hck, were also noted in the peritoneal resident cells from Tgm, whereas the level of mitogen-activated protein kinase (MAPK) activity was almost the same as that of non-Tgm. It was suggested that the low functional activities of Tgm Mphi seen in vivo were attributed to down-regulation of the unique transducing system of hMCP-1 signals under the influence of a high concentration of the hMCP-1. It seemed that the depressed functions were recovered when the peritoneal cells were released ex vivo from such a high hMCP-1 environment.

Multinucleated giant cell formation by microglia: induction by interleukin (IL)-4 and IL-13

To investigate the cellular origin and the mechanisms of multinucleated giant cell (MGC) formation in the CNS, various cytokines were applied to isolated murine microglia. All the single cytokines failed to induce MGC. However, interleukin (IL)-13 and IL-4 induced microglial MGC formation in the presence of colony stimulating factors, which was inhibited by either anti-IL-13 or anti-fms antibody. T helper 2 (Th2)-derived cytokines can induce MGC formation even in the absence of infectious agents.

Response of skin blood volume, velocity and flow to local warming in newborns, measured by laser Doppler flowmetry

BACKGROUND

In order to know the response of the skin microcirculation to local warming, we determined changes in the skin blood volume (Vol), velocity (Vel) and flow (F) by using a new laser Doppler device on newborns.

METHODS

The study subjects were 39 infants whose gestational age was 34.1 +/- 2.8 weeks and birth weight was 2189 +/- 572 g. The study was performed from 8 h postnatally to 28 postnatal days. We measured skin blood volume, velocity and flow at 36 degrees C (Vol36, Vel36, F36), and each value at 5 min (Vol44-5, Vel44-5, F44-5) and 10 min (Vol44-10, Vel44-10, F44-10) after local warming was applied at 44 degrees C and the response curve of each parameter was obtained. Subsequently, serial changes in the response of skin microcirculation to local warming were investigated in nine very low birth weight (VLBW) infants (28.3 +/- 0.9 weeks, 1150 +/- 148 g) and 12 low birth weight (LBW) infants (32.8 +/- 1.3 weeks, 1971 +/- 292 g). The F36, the increment rate of blood volume (delta Vol) and the increment rate of blood velocity (delta Vel) were obtained within 24 h, from day 1 to day 7 and from day 8 to day 30 in both VLBW and LBW infants and from day 31 to day 60 and at more than 61 days in VLBW infants. The F36, delta Vol and delta Vel were compared during the study periods in VLBW and LBW infants. All results were expressed as mean +/- SD.

RESULTS

The results showed that F36/F44-10 and F44-5/F44-10, Vol36/Vol44-10 and Vol44-5/Vol44-10, Vel36/Vel44-10 and Vel44-5/Vel44-10 were 0.25 +/- 0.09 and 0.74 +/- 0.17, 0.58 +/- 0.14 and 0.94 +/- 0.08, 0.42 +/- 0.12 and 0.79 +/- 0.15, respectively. Different modes of delivery did not have a significant effect on this response. The F36 in VLBW infants was high during the early neonatal period and gradually decreased with postnatal age. The delta Vol was low in VLBW infants during the neonatal period and gradually increased. The F36 in VLBW1-7 was significantly higher than in LBW1-7 (P < 0.01) and full-term controls (P < 0.001). The delta Vol in VLBW1-7 was 0.26 +/- 0.23, which is significantly lower than in LBW1-7 (0.57 +/- 0.17, P < 0.001) and full-term controls (0.77 +/- 0.21, P < 0.001). The delta Vel in VLBW1-7 and LBW1-7 was significantly higher than in controls (P < 0.05).

CONCLUSIONS

The skin blood flow increased continuously when local warming was applied at 44 degrees C. This high blood flow and limited potential of vasodilatation are the characteristics of the skin microcirculation in VLBW infants during the neonatal period.

[A case with HTLV-I associated myelopathy (HAM) accompanied by primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH)]

We reported a 60-year-old female patient with HTLV-I associated myelopathy (HAM) accompanied by primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH). The diagnosis of PBC and AIH was confirmed by liver biopsy. HAM is considered to be mediated by cellular immune mechanisms, while humoral immune mechanisms may play a predominant role in the development of PBC and AIH. Flowcytometric analysis of lymphocyte subset of peripheral blood was within normal limits. We then collected CD4 positive cells from the patient. These cells expressed T helper 2 (Th 2) cytokine mRNA such as IL-4 and IL-10, but did not express Th 1 cytokines, indicating the predominance of Th 2 in this patient. This case suggested the possibility that disease associated Th 2 might develop in the course of Th1-mediated disease like HAM.

[A case of acute transverse myelopathy and bilateral optic neuritis associated with anticardiolipin antibodies, lupus anticoagulant and perinuclear antineutrophil cytoplasmic antibodies]

A 69-year-old woman developed paraplegia and hypesthesia on upper extremities and below T4 level. Examination of cerebrospinal fluid showed increased protein levels and pleocytosis. MRI of the cervical spinal cord revealed syrinx formation from C3 to upper thoracic cord. A diagnosis of acute transverse myelitis was made. A high dose of corticosteroid including pulse therapy did not improve her symptoms and signs of myelopathy, but the syrinx could not be found thereafter. One year later, she developed severe visual loss due to bilateral optic neuritis which was improved spontaneously. The clinical course and MRI findings were similar to those of the optic-spinal form of multiple sclerosis (MS). The presence of anticardiolipin antibodies, lupus anticoagulant and perinuclear anti-neutrophil cytoplasmic antibodies, however, strongly suggested that vasculitic and/or ischemic mechanisms induced by these autoantibodies might play a role on the development of the disease. We conclude that our case should be distinguished from MS.

Electrophoretic mobility study on ion-ion interactions in an aqueous solution

Ion-ion interactions between anions and their pairing ions in aqueous solutions were studied through the measurements of electrophoretic mobilities of analyte ions in capillary zone electrophoresis, where the electrophoretic method for the analysis of ion association reaction is shown to be more useful than the conductometric method widely used in the analysis of the reactions. The electrophoretic mobility of monovalent inorganic anions was almost identical even when the concentrations of alkali metal ions and quaternary ammonium ions in the migrating solution were varied up to 15 mM. On the other hand, the electrophoretic mobility of organic anions, such as monovalent and divalent anions, decreased with increasing concentrations of quaternary ammonium ions. Changes in the electrophoretic mobilities were analyzed by a non-linear least-squares method giving ion association constants. The results indicate that the proposed method is applicable to the analysis of such reactions to give the mobility change. The ion association constants obtained in an aqueous solution were related to the extraction constants of the ion associates, and the contributions of the association process and the distribution process were clarified.

Equilibrium analysis of reactions between aromatic anions and nonionic surfactant micelles by capillary zone electrophoresis

Separability of some positional isomers of aromatic anions by capillary zone electrophoresis was improved by adding nonionic surfactants to a migrating solution. Eleven kinds of aromatic anions, including positional isomers, were used as analytes, and Brij-35, Brij-58 and Brij-78 were investigated as nonionic surfactants to form micelles, where hydrophobicities are different from each other. Increasing the concentration of the surfactants developed the separability of the anionic isomers. The interaction between the anions and the nonionic surfactant micelles is also investigated through the change in the electrophoretic mobility, and the binding constants are determined. Apparent electrophoretic mobility of the anions decreased with increasing concentrations of the nonionic surfactants. The decrease in the mobility, as well as the binding constant, was larger in the monovalent anions than in the divalent anions, which indicates that the interaction or reactivity of the monovalent analytes is higher than that of the divalent analytes. The reactivity of each anion was almost identical even when the kinds of the surfactants were changed, suggesting that the hydrophobicity of the polyoxyethylene group in the surfactant would have the main role for binding the analytes. The reactivity tendency among the positional isomers was almost similar to that in ion association-capillary zone electrophoresis using tertabutylammonium ion as a pairing ion. The results obtained in this work suggest that the anions are bound to the micelles by the hydrophobic interaction between analyte anions and the polyoxyethylene moiety of the surfactant micelles. Changes in the fluorescence intensity of the anions were also investigated; the results can explain well the mobility changes of the analytes.

Modulation by endothelin-1 of lipopolysaccharide-induced cyclooxygenase 2 expression in mouse peritoneal macrophages

We investigated the modulation by endothelin-1 of lipopolysaccharide-induced cyclooxygenase 2 expression and prostaglandin E2 production by mouse peritoneal macrophages. Our previous report showed that endothelin-1 at concentrations above 10(-11) M induced cyclooxygenase 2 expression through mainly endothelin ET(B) receptors and that an endothelin ET(B) receptor-mediated process was not involved in cyclooxygenase 2 activation in macrophages stimulated by lipopolysaccharide for 4 h. In the present study, when macrophages were stimulated by lipopolysaccharide for 12 h in the presence of endothelin-1 (10(-15) to 10(-8) M), cyclooxygenase 2 expression and prostaglandin E2 production were enhanced by 1.2- to 1.6-fold. The endothelin ET(B) receptor selective antagonist, BQ788 (N-cis-2,6-dimethylpiperidino-carbonyl-L-gamma-methyl-leucyl-D-L-m ethoxycarbonyl-tryptophanyl-norleucine), significantly inhibited this synergistic effect of endothelin-1. In addition, the cyclooxygenase 2-selective inhibitor, NS398 (N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide), also suppressed this effect. Western blot analysis showed that the endothelin ET(B) receptor was up-regulated by lipopolysaccharide in a time- and concentration-dependent manner, and that this up-regulation was inhibited by NS398. From these results, we conclude that endothelin-1 promotes lipopolysaccharide-induced cyclooxygenase 2 activation in the delayed phase through endothelin ET(B) receptors up-regulated by lipopolysaccharide.