PK/PD and safety of a single dose of TMX-67 (febuxostat) in subjects with mild and moderate renal impairment

A single oral dose of 20 mg febuxostat was administered to subjects with normal, mild or moderate impairment in renal function. There was less than a 2-fold difference in AUC of plasma unchanged febuxostat among the renal function groups, and changes in plasma urate levels from pre-dose levels were not significant. A total of five adverse events were reported with all mild in severity. The results indicate that renal impairment will have little clinical impact on the pharmacokinetics (PK), pharmacodynamics (PD) and safety of the study drug.

Pharmacokinetics and pharmacodynamics of febuxostat (TMX-67), a non-purine selective inhibitor of xanthine oxidase/xanthine dehydrogenase (NPSIXO) in patients with gout and/or hyperuricemia

The diurnal change of sUA and the effect of febuxostat on this change were investigated in 10 patients with gout and/or hyperuricemia. The diurnal sUA change after the last dose during the 4-week treatment phase (20 mg, QD) was almost the same as the pre-treatment value. Considering the dose, the AUC(obs) and Cmax of unchanged drug in patients with gout and/or hyperuricemia were estimated to be similar to those of healthy male adults. The results show that a 6-week treatment with febuxostat is safe and well-tolerated in the target patient population for this drug.

Preventive effects of sequential treatment with alendronate and 1 alpha-hydroxyvitamin D3 on bone mass and strength in ovariectomized rats

Because accumulating evidence has shown that bisphosphonates are unable to maintain their bone-sparing effects after the withdrawal of the drug, a replacement treatment is needed when bisphosphonate treatment cannot be continued for some reason. The present study investigated the preventive effects of alendronate followed by 1alpha(OH)D3 on the mass and mechanical strength of trabecular and cortical bones in ovariectomized rats. Sprague-Dawley rats were ovariectomized or sham-operated at 48 weeks of age. Ovariectomized rats treated with vehicle alone (OVX group) showed significant decreases in bone mineral density (BMD) and mechanical strength of the lumbar vertebra and the midfemur during a 20-week period after the operation as compared with sham-operated rats. These decreases were prevented by continuous treatment with alendronate (0.5 mg/kg/day, po) for 20 weeks (ALN-C group), whereas the values reverted to those of the OVX group when alendronate was withdrawn at 10 weeks (ALN-W group). The sequential treatment with alendronate and 1alpha(OH)D3 (0.05 microg/kg/day, po) for 10 weeks each (ALN --> 1alpha group) resulted in higher BMD and mechanical strength of the lumbar vertebra and the midfemur in this group than in the OVX and ALN-W groups. The increase in mechanical strength was proportional to that in BMD at both sites, suggesting that the stimulatory effects of these treatments on bone strength were due to those on bone mass. Analyses of histology, computed tomography, and biochemical markers confirmed the preventive effects of the sequential treatment. Therefore, we propose that 1alpha(OH)D3 may be a good choice to replace alendronate when alendronate treatment cannot be continued for some reason.

The role of mast cells in the development of 2, 4, 6-trinitrobenzene sulfonic acid-induced colitis in rats

BACKGROUND

The role of mast cells in Crohn disease (CD) remains to be established. The aim of this study was to elucidate this in the development of CD-like colitis in rats by the use of mast-cell-deficient Ws/Ws and their control W+/W+ rats.

METHODS

CD-like colitis was induced in both groups by an enema of 10 mg of 2,4, 6-trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Colonic damage, adhesion and colonic weight were measured at 7 and 14 days after the TNBS/ethanol enema. Rat mast cell protease-2 (RMCP-2) in the colonic tissue was also measured at 7 days after the enema.

RESULTS

There was no significant difference between W+/W+ and Ws/Ws rats in terms of colonic damage, adhesion or colonic weight. The tissue content of RMCP-2 in Ws/Ws rats treated with either saline or TNBS/ethanol was only maintained at a much lower level than that in W+/W+ rats with the corresponding treatment.

CONCLUSIONS

These results demonstrate that mast cells are not essential in the development of 2, 4, 6-trinitrobenzene sulfonic acid-induced colitis in rats.

Length of the flagellar hook and the capacity of the type III export apparatus

Length determination in biology generally uses molecular rulers. The hook, a part of the flagellum of motile bacteria, has an invariant length. Here, we examined hook length and found that it was determined not by molecular rulers but probably by the amount of subunit protein secreted by the flagellar export apparatus. The export apparatus shares common features with the type III virulence-factor secretion machinery and thus may be used more widely in length determination of structures other than flagella.

Peroxisome proliferator-activated receptors are expressed in human cultured mast cells: a possible role of these receptors in negative regulation of mast cell activation

We investigated the expression of peroxisome proliferator-activated receptors (PPAR) in human cultured mast cells (HCMC) by using the reverse transcription-polymerase chain reaction. HCMC expressed mRNA of PPARbeta, gamma1, and gamma2 constitutively, whereas PPARalpha was not detected. Though PPARgamma2 was expressed weakly, activation of HCMC with anti-IgE after IgE sensitization or with calcium ionophore plus phorbol ester resulted in increased expression of PPARgamma2 specifically. These stimuli did not influence the expression of PPARalpha and beta. In addition, provocation of HCMC with IgE or with IL-4 increased the mRNA level of PPARgamma2, and a synergistic effect was observed with the combination of IgE plus IL-4. To investigate a possible role of PPAR in mast cells, we examined the effects of PPAR agonists on cytokine production by HCMC. Prostaglandin (PG) D(2), Delta(12)-PGJ(2), 15deoxy-Delta(12, 14)-PGJ(2) (15d-PGJ(2)), and troglitazone, all of which are PPARgamma agonists, attenuated the production of granulocyte-macrophage colony-stimulating factor by anti-IgE-stimulated HCMC. A similar effect was observed with carbaprostacyclin, a PPARbeta agonist, but not with PPARalpha agonists. Anti-IgE-induced expression of cytokine mRNA, such as TNF-alpha, IL-5 and macrophage inflammatory protein-1alpha mRNA, was also reduced by the treatment with these PPARgamma agonists. Though only Delta(12)-PGJ(2) and 15d-PGJ(2) revealed an inhibitory effect on histamine release, leukotriene C(4) release from HCMC was suppressed by all tested PPARgamma agonists. These results indicate that HCMC express PPARbeta and gamma1/2, which might negatively regulate the activation of HCMC.

Effects of progesterone on the elevation of tail skin temperature in ovariectomized rats

We examined the effects of progesterone on the elevation of tail skin temperature (TST) in ovariectomized rats and compared them with those of estradiol. Progesterone showed only insignificant effects on the TST elevation, whereas estradiol showed complete inhibition. The TST elevation induced by ovariectomy is caused by estradiol deficiency, but progesterone plays little or no role.

Effect of activated human protein C on disseminated intravascular coagulation induced by lipopolysaccharide in rats

Protein C is the zymogen of an anticoagulant serine protease and is converted to its active form (activated protein C: APC) by thrombin in the presence of thrombomodulin. APC plays an important role in regulating coagulation and fibrinolysis by inactivating not only blood coagulation factors Va and VIIIa but also type-1 plasminogen activator inhibitor (PAI-1). The aim of the present study was to examine the effect of a human APC product (designated as CTC-111), compared with that of heparin, on the disseminated intravascular coagulation (DIC) induced by lipopolysaccharide (LPS) in rats. LPS (1 mg/kg/h) infusion was performed through a femoral vein for 4 h. One-fifth amount of the total dosage of CTC-111 or heparin was injected into the other femoral vein, followed by a 4-h infusion of the remainder. Both CTC-111 (10,000-100,000 U/kg) and heparin (400-800 IU/kg) inhibited the decrease in platelet count and fibrinogen level equally. The prolonged activated partial thromboplastin time and prothrombin time observed in DIC rats were further elongated in both CTC-111- and heparin-treated rats. But, this prolongation was less in CTC-111-treated rats than in the heparin-treated ones. Heparin inhibited the increase in fibrin and fibrinogen degradation products more prominently than CTC-111. On the other hand, CTC-111 strongly inhibited the increase in PAI-1 activity but heparin did not. These results suggest that CTC-111 may enhance fibrinolysis through its direct inhibitory effect on PAI-1. The parameters for liver or renal damage, i.e., plasma glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), creatinine (Cre) and blood urea nitrogen (BUN), were significantly increased by LPS infusion. Both CTC-111 (100,000 U/kg) and heparin (800 IU/kg) decreased the increase in GOT and GPT levels significantly, whereas neither affected the increase in Cre or BUN. From these results, the activation of the blood coagulation system might partially contribute to the progression of liver damage caused by LPS, and might be less involved in the progression of renal damage in this model. In conclusion, CTC-111 showed both anticoagulant and profibrinolytic activity in the LPS-induced DIC model without excessive prolongation of coagulation time. From these results, CTC-111 is expected to be a useful remedy for DIC without the risk of bleeding.

Effect of activated human protein C on experimental venous thrombosis induced by stasis with operative invasion in mice

Protein C (PC) is the zymogen of an anticoagulant serine protease and is converted to its active form (activated protein C: APC) by thrombin in the presence of thrombomodulin. APC plays an important role in regulating blood coagulation and fibrinolysis by inhibiting not only blood coagulation factors Va and VIIIa but also type-1 plasminogen activator inhibitor (PAI-1). In this study, it was reported that the antithrombotic effect of a human APC product (designated as CTC-111) compared with that of heparin and human PC on the deep venous thrombosis (DVT) model induced in mice by stasis caused by inferior vena cava ligation and operative invasion. Drugs were injected into a tail vein at -2, 30, 60, and 120 min after the inferior vena cava ligation. One-fifth amount of the total dosage of a given drug was injected at each time point. The wet weight of thrombus formed was reduced by APC or heparin administration, however, PC, which was equal to APC in protein amount, did not show any antithrombotic effect. To confirm whether human PC could be activated by mouse thrombin, PC was treated with mouse or human thrombin to measure the amount of APC formed. Mouse thrombin could activate human PC at a similar activation rate as human thrombin. These results suggest that externally administrated PC cannot exhibit antithrombotic effect in this DVT model due to slow activation rate to APC and that APC is a better antithrombic agent than PC for treating thrombotic diseases.

Effect of addition of Orvus ES paste to frozen canine semen extender on sperm acrosomes

Using the triple-stain technique, we investigated whether sperm acrosomes in frozen canine semen were protected during freezing and thawing by addition of a surfactant, Orvus ES Paste (OEP), to the extender. Acrosomes were clearly shown to be protected by the addition of OEP to the entender when compared with those in sperm frozen without OEP addition (p<0.05).

[Antiarrhythmic effects of pilsicainide hydrochloride and effects on cardiac function and ECG in dogs: comparison with disopyramide]

Antiarrhythmic effects and cardiovascular effects of pilsicainide hydrochloride were compared with those of disopyramide in a canine model of coronary ligation-induced ventricular arrhythmias and anesthetized dogs. Pilsicainide (1.25, 2.5 and 5 mg/kg) and disopyramide (2.5 and 5 mg/kg) decreased the arrhythmic ratio ¿(ventricular arrhythmias/total heart rate) x 100¿ dose-dependently. Pilsicainide at 2.5 and 5 mg/kg and disopyramide at 5 mg/kg suppressed ventricular arrhythmias more than 50%. The effective dose of pilsicainide was lower than that of disopyramide, but the effective plasma concentration of pilsicainide was between 3 and 8 micrograms/ml, which was almost the same as that of disopyramide. In anesthetized dogs, both drugs decreased LV dP/dt max in almost the same concentration-dependent manner. PQ-interval was prolonged by pilsicainide, but not by disopyramide. QRS and QTc were prolonged by both drugs in a concentration-dependent manner. However, the prolongation of QTc by disopyramide was provoked at lower plasma concentrations than by pilsicainide. Because the excessive prolongation of QTc lead to the lethal arrhythmias such as torsades de pointes, pilsicainide may be useful as an injectable antiarrhythmic agent superior to disopyramide.

Nephrotoxic effects of allopurinol in dinitrofluorobenzene-sensitized mice: comparative studies on TEI-6720

Allopurinol is widely used and generally well-tolerated. However, when used in patients with renal insufficiency it may have life-threatening toxic effects known as allopurinol hypersensitivity syndrome (AHS). We previously found that allopurinol increased ear swelling and mortality in a DNFB-induced contact hypersensitivity mouse model. In the present study, we investigated the toxic effect of allopurinol on DNFB-sensitized mice in order to clarify the mechanism responsible for the lethal effect of allopurinol. Allopurinol increased plasma GPT and GOT in DNFB-sensitized mice and markedly increased plasma creatinine and BUN. The increase in plasma GPT and GOT was moderate and declined time-dependently. In contrast, the increase in plasma creatinine and BUN was striking and continued until 18 hr after administration of allopurinol at 100 mg/kg/day. Although allopurinol increased GOT and GPT in DNFB-sensitized mice, no effect was observed in non-sensitized mice even at 100 mg/kg/day, indicating that allopurinol essentially has no toxic effect on the liver. A high dose of allopurinol induced renal impairment even in non-sensitized mice. These observations indicate that there is some biological interaction between allopurinol and DNFB, and suggest that allopurinol may modulate or enhance the inflammatory reactions induced by DNFB, and/or that DNFB may cause metabolic changes via inflammation, leading to the enhanced toxicity of allopurinol. In contrast, TEI-6720, a newly synthesized XOD/XDH inhibitor, had almost no effect on DNFB-sensitized mice. TEI-6720 at 1 mg/kg, in terms of hypouricemic effect, appeared to be more potent than allopurinol at 3 mg/kg. Therefore, the nephrotoxic effect of allopurinol observed in the present study may not be related to XOD/XDH inhibitory activity.

A comparative study on the hypouricemic activity and potency in renal xanthine calculus formation of two xanthine oxidase/xanthine dehydrogenase inhibitors: TEI-6720 and allopurinol in rats

In this study, the hypouricemic efficacy of a novel xanthine oxidase/xanthine dehydrogenase inhibitor, TEI-6720, was compared with that of allopurinol in a hyperuricemic rat model established by feeding the animals oxonate, a uricase inhibitor. In addition, using normal rats, the changes in xanthine concentration in plasma and the concentrations and absolute quantities of uric acid, allantoin and xanthine in urine were analyzed during a 28-day period of repeated administration of TEI-6720 to determine the changes occurring during this period and the conditions required for the formation of xanthine crystals and calculi in comparison with allopurinol. TEI-6720 and allopurinol caused a significant dose-dependent decrease in plasma uric acid levels in the hyperuricemic rat model and the ED50 of TEI-6720 was lower than that of allopurinol, indicating that in terms of hypouricemic efficacy TEI-6720 is more potent than allopurinol. TEI-6720 also showed more potent activity than allopurinol in decreasing urinary uric acid and allantoin levels in normal rats. In addition, TEI-6720 and allopurinol showed similar dose-response curves for the decrease in uric acid or allantoin concentration, and the associated increase in xanthine concentration, indicating that TEI-6720 and allopurinol have similar pharmacological characteristics although the dosage required differs. The efficacy of TEI-6720 in increasing plasma and urinary xanthine levels in normal rats was approximately 10- to 30-fold greater than that of allopurinol. However, with respect to renal xanthine calculus formation, there was only about a 3-fold difference in dosage comparing TEI-6720 and allopurinol. This difference suggests that there may be another factor independent of xanthine, and dependent on the drug itself, involved in renal calculus formation caused by allopurinol. The daily excretion of purine metabolites per body weight was about 20-fold higher in rats than in humans. From these results, it is concluded that TEI-6720 has potent hypouricemic activity and that, compared to allopurinol, administration of TEI-6720 is not likely to result in a higher incidence of calculus formation.

Allopurinol induces renal toxicity by impairing pyrimidine metabolism in mice

We investigated the relationship between the toxic effect of allopurinol and pyrimidine metabolism in mice. Allopurinol-induced increases in plasma transaminase levels in dinitrofluorobenzene (DNFB)-sensitized mice were not affected by uridine. In contrast, plasma creatinine and BUN tended to decrease 18 hr after the last injection of uridine. Both plasma and urinary orotidine (OD) were detected in DNFB-sensitized mice after administration of a single dose of allopurinol. In contrast, TEI-6720, a newly synthesized xanthine oxidase/xanthine dehydrogenase inhibitor, caused neither pyrimidine metabolism abnormality nor renal impairment in DNFB-sensitized mice. Also, normal mice administered high doses of allopurinol showed abnormal pyrimidine metabolism together with renal toxicity which could be ameliorated by uridine, indicating that allopurinol essentially causes pyrimidine metabolism abnormality leading to renal impairment. In DNFB-sensitized mice, allopurinol increased urinary OD excretion to an extent similar to that in normal mice administered the same dose of allopurinol. However, renal impairment by allopurinol was more striking in DNFB-sensitized mice than in normal mice. Histopathological observations showed that allopurinol induced calculus formation in the collecting tubules and papillary duct. Calculus formation was increased by DNFB and decreased by uridine. These observations indicate that the enhancement of the renal toxicity of allopurinol by DNFB-sensitization may be due to some biological interactions between DNFB and allopurinol. In humans, it is possible that there are some biological interactions which serve to enhance the toxicity of allopurinol, resulting in the development of allopurinol hypersensitivity syndrome (AHS). In contrast, TEI-6720, had no effect on pyrimidine metabolism and showed no toxic effect.

Elevation of tail skin temperature in ovariectomized rats in relation to menopausal hot flushes

Menopausal hot flushes (HFs), which manifest as an increase in skin temperature, most frequently occur after menopause and cease with the passage of time. We designed this study to elucidate the characteristics of the elevation of tail skin temperature (TST) in ovariectomized (OVX) rats, which is relevant to human symptoms of HFs. First, we measured TST and rectal temperature (RT) and investigated the time course of their changes up to 20 wk after ovariectomy. The TST in OVX rats (28.4 +/- 0.3 degrees C) was significantly (P = 0.0035) elevated from 2 to 7 wk after the ovariectomy compared with that in sham-operated (Sham) rats (27.0 +/- 0.2 degrees C), whereas the RT in OVX rats was elevated from 8 to 20 wk. We next examined the therapeutic effects of estradiol (E(2)) on the elevation of the TST by continuous subcutaneous infusion. E(2) treatment (1.0 microg/day) completely (P = 0.0232) inhibited the elevation of the TST (28.4 +/- 0.3 degrees C for Sham rats, 29.3 +/- 0.3 degrees C for OVX rats, 28.2 +/- 0.4 degrees C for OVX + E(2) 1.0 microg/day rats). These results demonstrated that the elevation of TST in OVX rats was exhibited soon after the estrogen removal and diminished with time and that it was normalized with continuous E(2) replacement. These characteristics are similar to the symptoms of menopausal HFs in women.

Peroxisome proliferator-activated receptors are expressed in mouse bone marrow-derived mast cells

We examined the expression of peroxisome proliferator-activated receptors (PPARs) and the role of PPARs in cytokine production in mouse bone marrow-derived mast cells (mBMMCs). mBMMCs expressed PPARbeta strongly and gamma slightly, but not alpha. Activation of mBMMCs with antigen or calcium ionophore resulted in the increased expression of PPARgamma mRNA specifically. 15-Deoxy-Delta(12, 14)-prostaglandin J(2) (15d-PGJ(2)) and troglitazone, all PPARgamma ligands, attenuated the antigen-induced cytokine production by mBMMCs. Carbaprostacyclin, a PPARbeta ligand, also inhibited cytokine production, whereas PPARalpha ligands did not. These results suggest that PPARbeta and gamma might be included in the negative regulation of mast cell activation.

Effects of ultrasound and 1,25-dihydroxyvitamin D3 on growth factor secretion in co-cultures of osteoblasts and endothelial cells

It has been shown that low-intensity pulsed ultrasound (US) accelerates fracture healing in animal models and in clinical studies. However, the mechanism by which US accelerates fracture healing remains unclear. Systemic factors and several growth factors, such as platelet-derived growth factor (PDGF), are thought to be involved in the process of fracture healing. In the present study, we examined the effects of US and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] on growth factor secretion in a co-culture system of human osteoblastic cells (SaOS-2) and endothelial cells (HUVEC). US was applied to cultured cells for 20 min daily for four consecutive days. US treatment increased the PDGF-AB level in the conditioned media. 1,25-(OH)2D3 (1 x 10(-8) M) also enhanced PDGF-AB secretion. The secretion of PDGF-AB was synergistically increased by the combination of US and 1,25-(OH)2D3. These results suggest that the stimulation of growth factor secretion from cells by US and 1,25-(OH)2D3 treatment may be involved in the acceleration of fracture healing.

Flagellar proteins and type III-exported virulence factors are the predominant proteins secreted into the culture media of Salmonella typhimurium

We analysed all major proteins secreted into culture media from Salmonella typhimurium. Proteins in culture supernatants were collected by trichloroacetic acid precipitation, separated in SDS-polyacrylamide gels and analysed by amino acid sequencing. Wild-type strain SJW1103 cells typically gave rise to nine bands in SDS gels: 89, 67, 58, 52, 50, 42, 40, 35 and (sometimes) 28 kDa. A search of the sequences in the available databases revealed that they were either flagellar proteins or virulence factors. Six of them were flagella specific: FlgK or HAP1 (58 kDa), FliC or flagellin (52 kDa), FliD or HAP2 (50 kDa), FlgE or hook protein (42 kDa), FlgL or HAP3 (35 kDa) and FlgD or hook-cap protein (28 kDa). The other four bands were specific for virulence factors: SipA (89 kDa), SipB (67 kDa), SipC (42 kDa) and InvJ (40 kDa). The 42 kDa band was a mixture of FlgE and SipC. We also analysed secreted proteins from more than 30 flagellar mutants, and they were categorized into four groups according to their band patterns: wild type, mot type, polyhook type and master gene type. Virulence factors were constantly secreted at a higher level in all flagellar mutants except a deltamot (motAB deletion) mutant, in which the amounts were greatly reduced. A new morphological pathway of flagellar biogenesis including protein secretion is presented.

Allopurinol increases ear swelling and mortality in a dinitrofluorobenzene-induced contact hypersensitivity mouse model

The immunomodulatory effects of allopurinol were investigated in a mouse contact hypersensitivity model. Allopurinol caused a time- and dose-dependent lethal effect in dinitrofluorobenzene (DNFB)-sensitized mice. Furthermore, allopurinol markedly increased ear swelling in the remaining mice. In contrast, TMX-67, a newly synthesized xanthine oxidase/xanthine dehydrogenase (XOD/XDH) inhibitor, had almost no effect on DNFB-sensitized mice. Allopurinol reduced both the spleen weight and white blood cell count in DNFB-sensitized mice without affecting the T cell subset of splenocytes. The production of interferon (IFN)-gamma, in the splenocytes of DNFB-sensitized mice was reduced by allopurinol administration. Death due to allopurinol was much lower in the non-sensitized mice than in the DNFB-sensitized mice. These findings indicate that allopurinol may interact with DNFB to enhance its toxicity and allopurinol might also modulate or enhance the inflammatory effect of DNFB. Also, DNFB may cause metabolic alterations via inflammation, leading to enhanced allopurinol toxicity.

Differential production of MCP-1 and cytokine-induced neutrophil chemoattractant in the ischemic brain after transient focal ischemia in rats

Chemokines have been shown to play an important role in leukocyte infiltration into ischemic lesions. Recently, the increased expression of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant (CINC) was observed in experimental stroke models where infiltrated leukocytes were supposed to induce tissue injury, however, the protein level and time course of these chemokines have not been fully elucidated. Therefore, we analyzed the time-dependent production of MCP-1 and CINC in the rat brain after transient middle cerebral artery occlusion (MCAO) by means of specific enzyme-linked immunosorbent assay systems. The MCP-1 levels in the ipsilateral hemispheres increased from 6 h, peaked at 2 days, and thereafter gradually decreased. The peak MCP-1 concentration was 89.2+/-28.2 ng/g tissue wet weight (mean +/- SEM, n = 5, 49.3-fold greater than the contralateral value at the same time, P < 0.05), which is supposed to be high enough to exert its biological effects. In contrast, the maximum CINC concentration that corresponded to 2.9+/-0.7 ng/g tissue wet weight (mean +/- SEM, n = 5, 55.0-fold greater than the contralateral value at the same time, P < 0.05), was observed at 6 h. In addition, we confirmed the temporal profile of leukocyte subtypes that infiltrated into the ischemic brain, thus, neutrophil infiltration occurred at early stages (1-3 days), followed by massive infiltration of macrophages at later stages (2-7 days). These studies suggest that MCP-1 in cerebral ischemia actually plays a significant role in the migration of macrophages into the lesion and that the differential temporal production of these chemokines contributes to the regulation of infiltrated leukocyte subtypes.

Regulation of RANTES and IL-8 production in normal human dermal fibroblasts by active vitamin D3 (tacalcitol)

1. The production of chemokines, RANTES and IL-8 in cultured human dermal fibroblasts and the effects of tacalcitol (1alpha,24(R)-dihydroxyvitamin D3) were studied using an enzyme-linked immunosorbent assay. 2. In the unstimulated condition, RANTES and IL-8 were at a trace level in the culture supernatant. On stimulation with TNF-alpha alone for 24 h, RANTES and IL-8 production were induced. Tacalcitol suppressed RANTES and IL-8 production dose-dependently at concentrations between 10(-12) M and 10(-7) M. 3. When the cells were treated with TNF-alpha and IFN-gamma in combination, RANTES production was enhanced, but IL-8 production was not changed, compared to TNF-alpha-treated cells. Tacalcitol decreased IL-8 production dose-dependently as observed in the TNF-alpha-treated cells. On the other hand, RANTES production was enhanced by 10(-11) M and 10(-10) M of tacalcitol, and dose-dependently suppressed by tacalcitol concentrations higher than 10(-9) M. 4. Active vitamin D3 compounds, betamethasone valerate and cyclosporin A were compared with respect to their effects on chemokine production. Three active vitamin D3 compounds, tacalcitol, 1alpha,25-dihydroxyvitamin D3 and MC903 (calcipotriol), inhibited the production of RANTES and IL-8, with very similar potencies. Betamethasone valerate also inhibited these chemokine productions, but with greater potency than active vitamin D3 compounds. Cyclosporin A significantly stimulated RANTES production at 10(-6) M and IL-8 production at 10(-7) M and 10(-6) M. 5. The results of this study suggest that active vitamin D3 compounds exert some beneficial effects in the treatment of inflammatory skin diseases via regulation of the production of chemokines by dermal fibroblasts.

Effects of continuous alendronate treatment on bone mass and mechanical properties in ovariectomized rats: comparison with pamidronate and etidronate in growing rats

Alendronate is a potent inhibitor of bone resorption. To investigate the relationship between antiresorptive activity and bone-related side effects, we studied the effect of 2 months of daily alendronate (0.04, 0.2, 1.0 or 5.0 mg/kg/day) treatment on the strength of the femoral shaft and neck and on the bone mass of ovariectomized rats. The p.o. administration regimen began immediately after ovariectomy at 6 weeks of age, and the results were compared with pamidronate (0.2, 1.0 or 5.0 mg/kg/day) or etidronate (5.0, 25.0 or 125.0 mg/kg/day) treatment. In the femoral epiphysis and neck, a preventive effect of alendronate on loss of bone mineral density was observed at the dose of 1.0 mg/kg. The alendronate-treated group did not show significant alteration of the breaking load or the cross-sectional shape of the femoral midshaft. Similar results were obtained in the femoral neck strength and femoral neck geometry. In histomorphometric analysis of tibial metaphyses, alendronate inhibited the ratio of osteoid volume to tissue volume and the mineral apposition rate at a dose of 0.2 mg/kg compared with the ovariectomized control. In contrast, etidronate tended to increase osteoid volume/bone volume at 125 mg/kg. From these results, we conclude that p.o. alendronate-treatment prevented the decrease in bone mineral density and maintained the mechanical properties of bone after ovariectomy without impairing of bone mineralization in growing rats.

RANTES expression in psoriatic skin, and regulation of RANTES and IL-8 production in cultured epidermal keratinocytes by active vitamin D3 (tacalcitol)

The chemokine RANTES is a chemoattractant for eosinophils, T lymphocytes of memory phenotype and monocytes, suggesting that it plays an important part in chronic inflammatory and allergic diseases. In various types of cells, RANTES production is markedly induced by tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma in combination. Psoriasis vulgaris is a chronic cutaneous inflammatory disease. Cytokines and chemokines produced by T cells and epidermal keratinocytes, such as interleukin (IL) 8, are involved in the pathogenesis of psoriasis. T-cell clones obtained from psoriatic skin have been shown to produce the Th1 cytokine IFN-gamma. In addition, abnormal expression of proinflammatory cytokines including TNF-alpha has been observed in psoriatic lesions. These reports led us to hypothesis that psoriatic skin could provide epidermal keratinocytes with TNF-alpha and IFN-gamma, so that keratinocytes could produce RANTES. In this study, we addressed the question as to whether RANTES was involved in psoriasis vulgaris. Immunohistochemistry of skin biopsies showed RANTES was present in the intercellular spaces between epidermal keratinocytes, in the fully developed lesions from the middle to the edge of psoriatic plaques, but not in the perilesional uninvolved and healthy control skin. Further, we confirmed the production of RANTES, together with IL-8, by cultured normal human epidermal keratinocytes, using an enzyme-linked immunosorbent assay. Stimulation with TNF-alpha and IFN-gamma in combination synergistically increased the RANTES production in this system. These results clearly demonstrate the expression of RANTES in psoriatic lesions and suggest the involvement of this chemokine in the outcome of cutaneous inflammatory diseases. Tacalcitol (1 alpha,24(R)-dihydroxyvitamin D3), an active vitamin D3 analogue, inhibited RANTES and IL-8 production in cultured normal epidermal keratinocytes. This result indicates that active vitamin D3 is effective in the regulation of chemokine production by epidermal keratinocytes, which may partly account for its action as an antipsoriatic drug.

Fc portion of intravenous immunoglobulin suppresses the induction of experimental allergic neuritis

To clarify how intravenous immunoglobulin (IVIg) acts on Guillain-Barré syndrome, we investigated the effects of intact-type IVIg treatment on experimental allergic neuritis (EAN) induced by immunizing with synthetic peptide from bovine P2 protein. Treatment with intact-type IVIg (400 mg/kg/day) on days 0, 7, 14, 15 and 16 after immunization prevented the paralysis, whereas treatment with F(ab')2 failed to alter the clinical course. Intact-type IVIg treatment given on days 0 and 1 showed almost the same efficacy. These results suggest that intact-type IVIg is superior to F(ab')2 in ameliorating the clinical course of EAN and that the Fc portion might affect the immune system.

Novel naphthalene derivatives as inhibitors of human immunoglobulin E antibody production

A series of naphthalene derivatives with a variety of substituents at the 2-position was prepared in order to evaluate their suppressive effect on immunoglobulin E (IgE) antibody production by human peripheral blood mononuclear cells provoked with anti-CD40 antibody (alpha-CD40), interleukin-4 (IL-4), and interleukin-10 (IL-10). Compounds having a 1,4-phenylene spacer moiety tethered between the 2-naphthyl nucleus and anthranilic acid suppressed IgE antibody production in vitro in preference to that of IgG antibody without affecting cell viability. Deletion of the anthranilic acid moiety diminished the inhibitory activities. Changing the 2-naphthyl to a 1-naphthyl or phenyl nucleus led to no change in the potency, indicating that the aromatic group at this position is indispensable for the inhibitory activities. On the other hand, changing the 1,4-phenylene spacer to a 1,3-phenylene one resulted in reduced potency. Similarly, inhibitory activities were lost when the CO2H moiety at the 2-position was moved to the 3- or 4-position on the terminal benzene. These observations suggest that the conformation around the anthranilic acid moiety affects the inhibitory activities toward IgE biosynthesis. 2-(4-(2-Naphthyloxy)benzamido)benzoic acid (29) seemed to be a more potent inhibitor of IgE production than of IgG production. Insertion of a methylene between the inter-phenylene and the amide moiety resulted in 2-((4-(2-naphthyloxy)phenyl)acetamido)benzoic acid (31), which provided a stronger inhibition of both IgE and IgG production, although the selectivity toward IgE was lower than that of 29. Introduction of a benzyl group at the 6-position on the naphthalene ring considerably increased the inhibitory activity toward IgE production with an IC50 of 8.3 nM (36). The potency of 31 and 36 was retained when hydrocortisone or lipopolysaccharide was used instead of alpha-CD40 and IL-10 as costimulatory factors with IL-4, implying that these compounds may interfere with signal transduction between IL-4/IL-4 receptor cognition and genetic transcription that induce class-switching of immunoglobulin in B cells. These novel naphthalene derivatives are thus excellent candidates for further investigation with a view toward a therapeutic remedy against IgE-mediated allergic diseases.

Effect of interleukin-10 on anti-CD40- and interleukin-4-induced immunoglobulin E production by human lymphocytes

We studied the effect of IL-10 on the in vitro synthesis of IgE and IgG by human peripheral blood mononuclear cells (PBMC) following stimulation with anti-CD40 monoclonal antibody and IL-4. Anti-CD40- and IL-4-stimulated PBMC showed an increase in IL-10 synthesis together with increases in IgE and IgG production. Addition of anti-IL-10 antibody to this system suppressed IgE as well as IgG production without affecting the proliferation of PBMC. Addition of IL-10 enhanced IgE and IgG production if PBMC were activated with anti-CD40 and IL-4. PBMC costimulated with anti-CD40, IL-4 and IL-10 showed a remarkable increase in IL-6 production, but had no effect on IFN-gamma production. Addition of IL-10 to purified human tonsillar B cells stimulated with anti-CD40 and IL-4 enhanced B cell proliferation and IgG production, but not IgE production. These results suggest that IL-10 accelerates IgE production by anti-CD40- and IL-4-stimulated PBMC by enhancing IL-6 production through activation of T lymphocytes.

Beneficial effects of a novel anti-hypoxemic agent, TEI-7322, on bleomycin-induced experimental hypoxemia in rats

Almitrine bismesylate is known to be an anti-hypoxemic agent that acts via the enhancement of hypoxic pulmonary vasoconstriction. However, screening for this class of compounds has been minimal, owing, in part, to a lack of convenient hypoxemic models in small animals. The present study was designed to establish a convenient model of hypoxemia induced by bleomycin and to evaluate anti-hypoxemic agents including a newly synthesized compound. TEI-7322, 2-allylamino-4-tert-butyl-amino-7-methyl-7H-pyrrolo[2,3- d]pyrimidine hydrochloride by using this model. Bleomycin was intratracheally instilled into rats. After 3 weeks, the arterial blood gas pressures were monitored in the animals in the conscious state. Then, prednisolone, doxapram, almitrine or TEI-7322 was administered to the bleomycin-treated rats to monitor changes in arterial blood gas pressures. Bleomycin-treated rats showed a decrease in the arterial blood O2 pressure (PaO2). The blood CO2 pressure (PaCO2) increased, along with an increase in the alveolar-arterial oxygen difference (AaDO2). These blood gas pressures in bleomycin-treated rats were not affected by treatment with prednisolone. Doxapram decreased the PaCO2 but did not change the PaO2. However, administration of almitrine or TEI-7322 significantly improved the PaO2 of bleomycin-treated rats with a decrease in the PaCO2. In conclusion, (1) bleomycin-induced lung injury causes hypoxemia in rats, probably resulting from ventilation-perfusion inequality; thus this model may be useful for evaluating anti-hypoxemic agents; and (2) TEI-7322, as well as almitrine, showed anti-hypoxemic effects in this model with different properties from those of doxapram, possibly due to improvement of ventilation-perfusion inequality, indicating that TEI-7322 may be a potent candidate for the treatment of hypoxemia.

Suppression of human immunoglobulin E antibody production by a new naphthalene derivative

A new naphthalene derivative, (E)-2-(7-(2-naphthyl)-6-heptenamide)benzoic acid (TEI-8364) was assessed for its effect on interleukin (IL)-4- and anti-CD40 monoclonal antibody-induced immunoglobulin E (IgE) production by cultured human lymphocytes. TEI-8364 preferentially suppressed the production of IgE by peripheral blood mononuclear cells (PBMC) in a dose-dependent manner, without inhibiting PBMC proliferation. In addition, TEI-8364, at a concentration of 10 microM, completely inhibited IL-4- and anti-CD40-induced IgE production by purified tonsillar B lymphocytes, suggesting that TEI-8364 affects B cells by interfering with signals provided by IL-4 or through CD40 and IL-4. TEI-8364 also had a profound inhibiting effect on the in vitro production of specific antibody to a T cell-dependent antigen by PBMC from an immunized volunteer, cultured in the presence of antigen. Furthermore, TEI-8364 at a dose of 1 mg/mouse/day selectively inhibited IgE production by severe combined immunodeficiency mice engrafted with human PBMC, if the drug was administered subcutaneously for five consecutive days. These findings suggest that TEI-8364 is a potent therapeutic agent that may be useful in the treatment of IgE-mediated allergic disorders.

Allele specificity of structural requirement for peptides bound to HLA-DRB1*0405 and -DRB1*0406 complexes: implication for the HLA-associated susceptibility to methimazole-induced insulin autoimmune syndrome

Self-peptides bound to HLA-DR4 (DRA-DRB1*0405 complex) were eluted from the purified DR4 complex, fractionated on reverse-phase HPLC, and subjected to NH2-terminal sequencing. Seven independent sequences were obtained, and all putative peptides synthesized bound to DRB1*0405 as well as DRB1*0406 complex, which differ only at DR beta residues 37, 57, 74, and 86. Binding assay using analogue peptides of a DR4 binder GSTVFDNLPNPE revealed that FxxLxN is an important anchor motif necessary for binding (where x is any amino acid), which was common to DRB1*0405 and 0406. Determination of the binding affinity of 60 synthetic AAFAALANAA-based analogue peptides showed that substituting F to W or C; L to F, W, or Y; and N to Q or S on AAFAALANAA changed the affinity substantially between DRB1*0405 and DRB1*0406. It is noteworthy that all patients with methimazole-induced insulin autoimmune syndrome are positive for DRB1*0406 and negative for DRB1*0405. Interestingly, the quantitative structural motif identified in this study predicted that 8TSICSLYQLE17 of human insulin alpha chain may bind specifically to DRB1*0406 using its 10IxxLxQ15 motif. Indeed, DRB1*0406 complex bound 8TSICSLYQLE17 with a high affinity, and in striking contrast, DRB1*0405 complex did not. Furthermore, a short-term T cell line specific to human insulin established from a DRB1*0406-bearing individual did show reactivity with a peptide fragment containing the 10IxxLxQ15 motif. Although this fragment probably exists at a very low level under normal physiological conditions due to the disulfide bond between flanking cysteine residues (6Cys-11Cys), a reducing compound such as methimazole may cleave the disulfide bond in vivo and allow DR alpha-DRB1*0406 complex on antigen-presenting cells to bind much of the linear fragment of insulin alpha chain, which may lead to the activation of self-insulin-specific T-helper cells.

Hypouricemic effect of allopurinol and the novel xanthine oxidase inhibitor TEI-6720 in chimpanzees

The hypouricemic effect of a newly synthesized xanthine oxidase/xanthine dehydrogenase inhibitor, TEI-6720, 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylic acid, was investigated and compared with that of allopurinol in male chimpanzees (n = 3). When allopurinol (10 mg/kg) was administered orally once a day for three consecutive days, it cumulatively reduced serum urate levels by 29.7, 50.1 and 60.2%, 24, 48 and 72 h, respectively, after the initial dose. This effect was dose dependent at doses of 3 and 10 mg/kg. At 3 mg/kg, the mean serum urate levels were 3.1, 2.4, 2.5 and 2.3 mg/dl before and 24, 48 and 72 h, respectively, after the initial dose. Animals treated with 10 mg/kg of allopurinol showed serum urate levels of 3.3, 2.3, 1.6 and 1.3 mg/dl, respectively. The urate-lowering effect of TEI-6720 was then compared with that of allopurinol at a daily dose of 5 mg/kg (n = 3). Both compounds caused striking reductions in serum and urinary uric acid levels accompanied by an increase in urinary xanthine levels. These effects of TEI-6720 were more potent than those of allopurinol. TEI-6720 reduced serum urate levels by 55.9, 69.6 and 73.6%, 24, 48 and 72 h, respectively, after the first dose, whereas the corresponding values after allopurinol were 28.1, 41.6 and 45.1%. These results suggest that the hypouricemic effect of TEI-6720 may be more potent than that of allopurinol in the treatment of hyperuricemia and gout, and that TEI-6720 may become an effective alternative drug.

Hypouricemic effect of the novel xanthine oxidase inhibitor, TEI-6720, in rodents

We investigated the xanthine oxidase/xanthine dehydrogenase inhibitory activity and hypouricemic effect of a newly synthesized xanthine oxidase/xanthine dehydrogenase inhibitor, TEI-6720, 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazole-carboxylic acid, and compared its effects with those of allopurinol in rodents. TEI-6720 was found to inhibit bovine milk xanthine oxidase, and mouse liver and rat liver xanthine oxidase/xanthine dehydrogenase with IC50 values of 1.4, 1.8 and 2.2 nM, respectively. On bovine milk xanthine oxidase, TEI-6720 exhibited mixed-type inhibition and the Ki value was 0.7 nM. TEI-6720 displayed prolonged urate-lowering activity in normal mice and rats. We evaluated the hypouricemic effect of TEI-6720 on hyperuricemia induced by the uricase inhibitor, potassium oxonate (250 mg/kg s.c., 1 h before the test drugs), and measured the total molarity of both serum allantoin and urate in rats. Oral TEI-6720 and allopurinol had a hypouricemic effect 2 h after their administration to oxonate-pretreated rats with ED50 values of 1.5 and 5.0 mg/kg, respectively. Both compounds also reduced the combined molarity of uric acid and allantoin in rats. The ED50 values of TEI-6720 and allopurinol were 2.1 and 6.9 mg/kg p.o., respectively. These results suggest that TEI-6720 may be useful for the treatment of hyperuricemia.

1,25-Dihydroxyvitamin D3 inhibits thromboxane release from activated macrophages

1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) in concentrations from 0.1 to 10 nM suppressed immunoreactive thromboxane B2 (iTXB2) release from Propionibacterium acnes (P. acnes)-elicited liver adherent cells stimulated with lipopolysaccharide (LPS, 1 microgram/ml). These suppressive effects of 1,25-(OH)2D3 were also observed in oyster glycogen-elicited peritoneal macrophages. On the contrary, it did not inhibit iTXB2 release from both resident Kupffer cells and peritoneal macrophages stimulated with the same concentration of LPS. Furthermore, 1,24(R)-dihydroxyvitamin D3 (1,24(R)-(OH)2D3), a vitamin D3 analogue, also inhibited iTXB2 release from liver adherent cells, but, another synthesized vitamin D3 analogue, 1 alpha-hydroxyvitamin D3 (1 alpha-OH-D3) tended to decrease iTXB2 release only at higher concentrations. These results suggest that active vitamin D3 analogues inhibit iTXB2 release from activated macrophages.

Inhibitory effect of activated protein C on platelet aggregation induced by the prothrombin-converting reaction

The present study was undertaken to elucidate the effect on platelet aggregation of the prothrombin-converting reaction on platelets with or without activated protein C (APC). A reaction mixture of washed platelets from human individuals, Factor Xa and prothrombin markedly induced platelet aggregation; maximum aggregation rates, 31.3-92.5%, and times to reach to maximum aggregation, 11.6 to 20.1 min. This aggregation was inhibited by the addition of APC with 50% inhibition concentration (IC50) value of 14.4 U/ml. APC also inhibited thrombin generation in the reaction mixture in a dose-dependent manner with IC50 value of 0.96 U/ml. However, APC did not inhibit the thrombin (0.1 CU/ml)-induced platelet aggregation at concentrations of up to 30 U/ml. These findings suggest that APC has no direct inhibitory effect on platelet aggregation and that APC inhibits platelet aggregation through inhibition of thrombin generation.

Characterization of immunomodulating action of TI-31 on antibody response in mice

TI-31, at concentrations of 10 and 100 microM, suppressed the antibody response to T cell-dependent (sheep red blood cells, SRBC) and -independent antigens (trinitrophenyl-lipopolysaccharide, TNP-LPS and TNP-Ficoll). The anti-SRBC response was suppressed by TI-31 when T cells were replaced by a supernatant of concanavalin A (Con A)-stimulated spleen cells, indicating the drug had influence on T lymphocytes, B lymphocytes and macrophages. TI-31 augmented the Con A-induced suppressor T cell (Ts) assessed by anti-SRBC plaque-forming cells response in vitro. The drug (10 mg/kg, p.o.) potentiated antigen specific Ts induction in vitro after injection of a high dose of SRBC. The results demonstrate that TI-31 enhanced Ts induction, which resulted in a diminution of antibody formation.

Protective effect of vitamin D3 analogues on endotoxin shock in mice

The effect of vitamin D3 analogues on endotoxin shock in mice was investigated. Male ICR mice were orally administered vitamin D3 analogues or vehicle, accompanied by an intraperitoneal injection of endotoxin (E. Coli lipopolysaccharide, LPS, 20 mg/kg). Endotoxin caused a decrease in survival rate in a time-dependent manner. Increases in plasma immunoreactive (i) eicosanoid and hepatic malondialdehyde (MDA) levels were also observed. Administration of 1 alpha-hydroxyvitamin D3 (1 alpha-OH-D3) improved the survival rate 24 to 48 h after endotoxin treatment. The effects were markedly observed at a dose of 20 ng/kg. In addition, 1 alpha-OH-D3 restored the plasma iTXB2 and hepatic MDA levels 8 h after endotoxin injection. However, it did not affect plasma iPGE2, i6-keto-PGF1 alpha and blood iLTB4 levels. At a dose of 20 ng/kg, both 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) and 1,24(R)-dihydroxyvitamin D3 (1,24(R)-(OH)2D3) restored the survival rate, the plasma iTXB2 and hepatic MDA levels. These results suggest that vitamin D3 analogues may inhibit endotoxemia through regulation of the formation of TXA2 and free radicals.

Effects of cimetidine on quinidine distribution in rats

The effects of cimetidine on the time course of plasma concentration, plasma protein binding and tissue distribution of quinidine were studied in rats. The plasma disappearance of quinidine after a 25 mg/kg intravenous injection was fitted to a two compartment open model. In the cimetidine-treated rats (50 mg/kg), the pharmacokinetic parameters of quinidine, such as the plasma total body clearance (Cltot), the volume of distribution at steady state (Vdss) and the elimination rate constant of the central compartment (kel) decreased to 62, 60 and 73%, respectively of those of the non-treated rats. The plasma concentration of quinidine at steady state, after an intravenous injection (20 mg/kg body weight) followed by a constant rate infusion (0.2 mg/min/kg), increased from 3.02 to 5.11 micrograms/ml after cimetidine treatment. The tissue-to-plasma concentration ratio (Kp) of heart, brain and muscle, determined in homogenates at steady state, decreased after cimetidine treatment. The effect of cimetidine lasted several hours after a cimetidine bolus intravenous injection. These decreases of Kp could satisfy quantitatively the decrease of Vdss. It may be concluded that the decrease of Vdss was due to the inhibition of tissue distribution (binding and/or partition to tissue components) of quinidine by cimetidine treatment.

Anti-arthritic and immunoregulatory effects of TI-31 on collagen-induced arthritis

TI-31 (TEI-3096, 6-p-chlorobenzyl-5H-2,3,6,7-tetrahydro-5,7-dioxothiazolo[3,2-a]pyr imidine) reduced bovine type II collagen-induced arthritis (CIA) in rats in a time- and dose-dependent manner. Oral TI-31 treatment in doses of 10 and 50 mg/kg daily for 7 days prior to collagen immunization depressed the development of arthritis. However, it had no obvious effect on CIA when administered daily for a 7-day or 28-day period after the immunization. This compound was also ineffective against the established arthritis. On the contrary, cyclophosphamide, dexamethasone, or ibuprofen strongly protected the animals from the development of arthritis and/or cured the established arthritis by these dose regimens. Both humoral and delayed-type hypersensitivity skin responses to bovine type II collagen were decreased in rats treated with TI-31 daily for 7 days before the induction of arthritis. These results suggest that TI-31 depresses CIA by regulating the immune response to collagen through a mechanism different from that of anti-inflammatory drugs or immunosuppressants.

Inhibitory effect of TI-31 on autoimmune nephritis in NZB/NZW F1 mice through regulation of the immune response

TI-31 (TEI-3096; 6-p-chlorobenzyl-5H-2,3,6,7-tetrahydro-5,7-dioxothiazolo[3,2-a]pyr imidine) is a novel immunomodulator. Various nephritic changes observed in female NZB/NZW F1 (B/W) mice with aging were suppressed by TI-31 when administered orally 5 times per week for 16 weeks at doses of 2, 10, or 50 mg/kg. It suppressed proteinuria, oliguria, the decrease of erythrocyte count, and increase of serum urea nitrogen, immune complex and anti-double-stranded DNA antibody levels. The anti-nephritic effect of TI-31 was confirmed by histopathological evaluation. TI-31 (10 mg/kg) could improve both the elevated polyclonal B cell activation and the depressed antibody response to sheep red blood cells in B/W mice, in comparison with age- and sex-matched BALB/c mice, without any effect on the antibody response in these normal mice. These findings indicate that TI-31 may inhibit B/W nephritis by regulating the antibody production through a mechanism different from that of anti-inflammatory drugs or immunosuppressants.

1,25-Dihydroxyvitamin D3 and 1,24-dihydroxyvitamin D3 suppress in vitro antibody response to T cell-dependent antigen

1,25-Dihydroxyvitamin D3 and 1,24-dihydroxyvitamin D3 suppressed an antibody response to sheep red blood cells (SRBC, T cell-dependent antigen) by murine splenocytes, in concentrations ranging from 10(-10)-10(-7)M. These suppressive effects were markedly abrogated when T cell-depleted lymphocytes were cultured in the presence of a supernatant of concanavalin A-stimulated spleen cells. On the contrary, neither of them suppressed antibody response to trinitrophenyl-lipopolysaccharide (T cell-independent antigen). These results suggest that the suppressive effect of active vitamin D3 on anti-SRBC response was mediated by the inhibition of T cells.

Effects of corticosteroid and 1,24R-dihydroxy-vitamin D3 administration on lymphoproliferation and autoimmune disease in MRL/MP-lpr/lpr mice

The pharmacological effects of prolonged administration of a corticosteroid, betamethasone, and active vitamin D3 [1,24R-(OH)2D3] on lymphoproliferation and autoimmune disease of MRL/MP-lpr/lpr (MRL/1) mice were examined. Relatively high doses of betamethasone (0.25 mg/kg/day) prevented lymphoproliferation, reduced serum levels of anti-dsDNA, anti-ssDNA, and anti-poly (ADP-ribose) antibodies, and brought about clinical improvement, such as reduced proteinuria and diminution of skin lesions. It is noteworthy that not only did prevention of lymphoproliferation occur, but also recovery of the Lyt-2+ T cell subset in the thymus and the spleen was observed. The administration of 1,24R-(OH)2D3 (0.1 microgram/kg/day) similarly prevented proteinuria, and produced recovery of a Lyt-2+ subset in the thymus.

Abnormality of the delayed type hypersensitivity (DTH) response to Bordetella pertussis in spontaneously hypertensive rats (SHR)

The delayed type hypersensitivity (DTH) response of spontaneously hypertensive rats (SHR) was compared with that of Wistar Kyoto rats (WKY), a normotensive strain. SHR showed a lower DTH response to Bordetella pertussis than WKY, especially 48 to 72 hr after antigenic challenge. These results were observed before appearance of abnormality of antibody formation or blood pressure. The reduced DTH responses of SHR were partially restored by either transfer of WKY thymocytes or treatment with levamisole. Conversely, the transfer of SHR thymocytes into WKY rats tended to diminish the DTH response. These findings suggest that SHR have a disfunction of T lymphocytes involved in DTH response (e.g., increase of suppressor cells and/or decrease of helper cells).

An experimental model of nephritis induced by calf serum injection in mice

Acute glomerulonephritis characterized by proteinuria, hypoalbuminemia and leukocytosis was induced in mice by repeated intraperitoneal injections of calf serum (1 ml/mouse X 10). In mice treated with calf serum, hypercellularity, karyorrhexis, expansion of the mesangium and hyalinosis in the glomeruli were observed by light microscopy. Furthermore, circulating immune complexes were detected in the serum, and deposits of mouse IgG and C3 on the basement membranes of the glomeruli were demonstrated immunohistochemically. Oral administration of cyclophosphamide or 6-mercaptopurine at a dose of 20 mg/kg/day significantly suppressed the development of this nephritis. Dexamethasone (0.5 mg/kg/day) caused moderate inhibition of the nephritic changes. These results suggest that this experimental model may be useful for evaluation of anti-nephritic drugs.

Immunopharmacological profile of TEI-3096: a new immunomodulator

TEI-3096 [6-p-chlorobenzyl-5H-2,3,6,7-terahydro-5,7-dioxothiazolo (3,2-a) pyrimidine], a novel thiazolopyrimidine compound has been shown to suppress adjuvant arthritis in rats without any effect on conventional inflammation. We examined the immuno-pharmacological profile of TEI-3096 in murine lymphocytes. The blastformation induced by Con A or LPS was inhibited by addition of 50-500 microM concentrations of TEI-3096. This compound suppressed elevated plaque-forming cell (PFC) response against T cell-dependent antigen. However, TEI-3096 had no effect either on normal PFC response or on antibody formation against T cell independent antigen. Although orally administered TEI-3096 had no obvious effect on anti-SRBC PFC response in normal mice, it normalized the colchicine-induced enhancement of antibody formation against TNP-HGG. TEI-3096 also enhanced the delayed type hypersensitivity in mice and rats. These results suggests that TEI-3096 restores the abnormal immune response. Therefore, it may be useful for the treatment of auto-immune disease such as rheumatoid arthritis.

Inhibition of prostaglandin synthesizing enzymes by haptoglobin and plasma of rats with inflammation

Administration of carrageenin or adjuvant to rats to induce inflammation produced increases in the plasma haptoglobin level. Simultaneously, there was an increase in the activity of the plasma inhibitor of prostaglandin E2 synthesis. Partially purified haptoglobin inhibited the microsomal over-all conversion of arachidonic acid to prostaglandin E2. The addition of the haptoglobin inhibited two heme-dependent reactions catalyzed by a purified enzyme of seminal vesicle microsome, i.e., the prostaglandin G2 synthesis from arachidonic acid and the conversion of prostaglandin G2 to H2. However, the plasma inhibitory activity was accounted for only partially by the haptoglobin contained in the plasma from treated rats.