Immunomodulatory effect of a newly synthesized compound, TOK-8801 (N-(2-phenylethyl)-3,6,6-trimethyl-5,6-dihydroimidazo [2,1-b]thiazole-2-carboxamide) on antibody production in vivo and delayed-type hypersensitivity in mice

The immunopharmacological effects of a newly synthesized compound in vivo, TOK-8801 (N-(2-phenylethyl)-3,6,6-trimethyl-5,6-dihydroimidazo[2,1-b]thi azo le-2- carboxamide), on the anti-SRBC plaque-forming cell (PFC) response and delayed-type hypersensitivity (DTH) reaction were investigated. Oral administration of TOK-8801 (0.1-10 mg/kg) resulted in the suppression of the PFC responses to varying doses of antigen (5 x 10(6), 2 x 10(7), 1 x 10(8)) in C3H/He strain mice (7 W) which are high responders to SRBC antigen. On the other hand, the compound augmented the PFC response in aged mice (8-9 months) in which the PFC response was markedly depressed compared with that in young mice. In the experiment of the methylated human serum albumin-induced DTH reaction, TOK-8801 augmented the reaction in low responder (C57BL/6) mice by oral administrations of 0.1-1 mg/kg for 5 days from the sensitization, whereas suppressed the reaction in high responder (ICR) mice. These immunopharmacological actions of TOK-8801 were compared in dose and activity with those of lobenzarit and bucillamine. Thus, these results suggest that TOK-8801 may act as an immunomodulating agent and would be expected to be a useful agent for autoimmune diseases such as rheumatoid arthritis.

Intracellular accumulation of isoproterenol enhances the lactate production in the perfused rat heart

Effects of intracellular accumulation of isoproterenol (ISO) on lactate production were examined in perfused rat heart. The lactate production during ISO perfusion in rat heart was increased and subsequent addition of an inhibitor of catechol-O-methyl transferase (COMT) further enhanced the production, and the enhanced production was significantly reduced by uptake2 inhibitor. The perfusion with ISO free-medium in the heart with high intracellular accumulation of ISO produced lactate more than that in the low intracellular accumulation. The present experiments demonstrated that the enhanced lactate production is accompanied by intracellular accumulation of ISO in the perfused rat heart, and suggested that the accumulated ISO may activate intracellular beta-adrenoceptors in the rat heart.

In vivo changes in brain catecholamine release from rat hypothalamus following olfactory bulbectomy

The mechanism eliciting mouse-killing behavior (muricide), induced by bilateral olfactory bulbectomy, has been shown to involve the brain noradrenergic system; this is because muricide is specifically inhibited by the drugs which potentiate the activity of catecholaminergic neurons such as tricyclic antidepressants. Our previous reports also demonstrated that the hypothalamic noradrenaline (NA) contents increased in the rats which exhibited muricide. To further examine the hypothalamic noradrenergic function in muricide, a push-pull perfusion technique was applied for direct measurement of NA release from the lateral (LH) and ventromedial (VMH) hypothalamus in freely moving rats. Subsequently, the perfusates, including catecholamines and their metabolites were measured by means of high-performance liquid chromatography with electrochemical detection (HPLC-ECD). Three days after olfactory bulbectomy, 67% of the rats elicited muricide and NA release from LH tended to decrease. Moreover, 7 days after olfactory bulbectomy, most of the rats elicited muricide and NA release from LH was significantly decreased, but not from VMH. On the other hand, dopamine (DA) release from VMH without LH conversely increased on the 7th day after olfactory bulbectomy. These results suggest that the dysfunction of the noradrenergic system caused by the decrease in NA release from LH played an important role for the incidence of muricide.

Immunomodulatory activity of the newly synthesized compound TOK-8801 (N-(2-phenylethyl)-3,6,6-trimethyl-5,6-dihydroimidazo[2,1-b]thiazole-2- carboxamide)

The in vitro and in vivo effects of the newly synthesized compound TOK-8801 (N-(2-phenylethyl)-3,6,6-trimethyl-5,6-dihydroimidazo[2,1-b] thiazole-2-carboxamide) on immune responses were investigated in comparison with that of levamisole (LMS). TOK-8801 enhanced the anti-sheep red blood cells (SRBC) plaque forming cells (PFC) response and mitogen-induced proliferative responses in murine splenocytes and thymocytes in vitro at concentrations of 10(-7)-10(-5) M, while LMS augmented these responses at 10(-4) M. The stimulatory effect of TOK-8801 as well as LMS on the antibody production was eliminated by the removal of T cells. TOK-8801 (0.5 mg/kg, p.o.) suppressed the in vivo generation of anti-SRBC PFC in normal mice, but the compound restored the depressed antibody production in restraint-stress mice which was mainly caused by helper T cell defects. From these results, TOK-8801 was shown to have an immunomodulatory activity in the antibody production.

Activities of dipeptidyl peptidases in BXSB mice and MRL/lpr mice with lupus erythematosus-like syndrome

Activities of peptidases were examined in tissues of male BXSB and male MRL/Mp-lpr/lpr (MRL/lpr) mice which are animal models of human systemic lupus erythematosus. Female BXSB and male MRL/+ + mice without histopathological changes were used as controls. Activity of DPP II in the spleen, kidney, and liver showed an increase at 13 and 20 weeks of age, while that of DPP IV was decreased at 20 weeks of age, as compared to control mice. The ratio of DPP II/DPP IV activities in the tissues was significantly increased and these findings agree with our previous results in the tissues of NZB mice and in the serum of patients with lupus erythematosus, underscoring the importance of hydrolytic enzymes in the pathogenesis of autoimmune diseases.

Ascorbic acid suppresses the deconjugation of noradrenaline but not dopamine in plasma

The characteristics of hydrolysis of sulfoconjugated noradrenaline (NA) and dopamine (DA) in plasma using sulfatase were investigated. Ascorbic acid has been used as an antioxidant during the hydrolysis of conjugated NA or DA. Hydrolysis of NA sulfates was considerably inhibited by adding ascorbic acid (0.5-10 mM), and slightly inhibited by adding dithiothreitol (1-10 mM). In contrast, the hydrolysis of DA sulfates was not affected after either ascorbic acid or DTT treatment. On the basis of these findings, the levels of NA sulfates previously reported are found to be markedly lower than the actual levels of NA sulfates in human plasma.

T-cell clones with L3T4-positive or Lyt-2-positive phenotypes responding to mutant MHC class II antigen and inducing graft versus host reaction

Two types of T cell clones responding to mutant major histocompatibility class II antigen (Iabm12) were established from spleen cells of C57BL/6 mice: one was L3T4-positive and the other Lyt-2-positive. These two types of clones carried functionally different properties. Lyt-2+ clones were absolutely dependent on exogenous interleukin-2 for their proliferation, whereas some L3T4+ clones secreted interleukin-2 and proliferated autonomously. Both types of clones had cytotoxic activities to bm12 target cells, and Lyt-2+ clones showed stronger activities than L3T4+ clones. Lyt-2+ clones induced induration in situ, whereas the L3T4+ clones induced ulcerative reaction when injected intradermally into mice. Histologically, the L3T4+ clones caused necrosis of the epidermis or upperdermis, while the Lyt-2+ clones induced infiltration of small round cells through the epidermis to the subcutaneous tissues and caused thickening of the epidermis. These characteristic reactivities might be due to a difference in lymphokines produced by each type of T cell subset in response to Iabm12 antigen.

Effects of nicotine on gastric contractile response to stimulation of the vagal afferent fibers in cats

Effects of nicotine on the delayed gastric contraction due to vagal afferent stimulation were studied. Cats were pretreated with phentolamine (2 mg/kg, i.v.) and propranolol (1 mg/kg, i.v.). The delayed contraction was inhibited by nicotine (100 to 2000 micrograms/kg, i.v.) in a dose-dependent manner. The inhibition of the delayed contraction by nicotine was blocked by hexamethonium (20 mg/kg, i.v.). The results suggested that nicotine inhibits the delayed contraction by activation of hexamethonium-sensitive inhibitory neurons in the vagal pathway to the stomach.

Relationship of calcium and adenylate cyclase messenger systems in rat brain synaptosomes

The effects of cyclic AMP on the rise in cytosolic free calcium concentration, [Ca2+]i, after stimulation with 15 mM K+ in rat brain synaptosomes were investigated. The fluorescent chelating agent Quin-2 was employed to monitor alterations of K+-evoked [Ca2+]i. Under normoxic conditions, clonidine (1, 10 microM), an alpha 2-adrenoceptor agonist, decreased the 15 mM K+-evoked [Ca2+]i. Although yohimbine (1, 10 microM), an alpha 2-adrenoceptor antagonist, had little or no effect on K+-evoked [Ca2+]i, the inhibitory effects of clonidine were blocked by yohimbine. 8-Bromo cyclic AMP, a cyclic AMP analogue, (50-500 microM), increased K+-evoked [Ca2+]i in a dose-dependent manner. The addition of cyclic AMP analogues subsequent to clonidine treatment reversed the clonidine-induced suppression of K+-evoked [Ca2+]i. On the other hand, under hypoxic conditions, K+-evoked [Ca2+]i was reduced by about 50-60%. 8-Bromo cyclic AMP and the adenylate cyclase activators, yohimbine (1-10 microM) and isoproterenol, a beta-adrenoceptor agonist, (0.1-10 microM), transiently reversed the reduction of the K+-evoked [Ca2+]i caused by hypoxia. These results indicate that the activation of alpha 2-adrenoceptor produces a rapid, sustained decrease in [Ca2+]i which may be due to a decrease in the levels of intracellular cyclic AMP. In addition, the increase in cellular levels of cyclic AMP reversed the reduction of the Ca2+ response to high K+ stimulation caused by hypoxia. If this is so, there is the possibility that increased cyclic AMP might improve the hypoxic damage.

Purification of the thromboxane A2/prostaglandin H2 receptor from human blood platelets

S-145 (5Z-7-(3-endo-phenylsulfonylamino-(2.2.1.)-bicyclohept -2-exo-yl) heptenoic acid) is a potent and selective antagonist for thromboxane A2/prostaglandin H2 receptor. Using this compound as an immobilized ligand for affinity chromatography and [3H]S-145 as a radioligand, we have purified the thromboxane A2/prostaglandin H2 receptor from the membranes of human blood platelets. The purification procedures consisted of solubilization of the receptor with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), affinity chromatographies on columns of S-145 affinity gel, wheat germ agglutinin agarose and red agarose, and repeated gel filtration high performance liquid chromatography on a TSK gel G-3000SW column. On the second gel filtration high performance liquid chromatography, the [3H]S-145 binding activity was eluted as a symmetrical peak which overlapped exactly with a peak of ultraviolet absorption at 280 nm. By these procedures, the receptor was purified about 8700-fold from the solubilized extract with a recovery of 6%. The final preparation showed a broad protein band at Mr 57,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and maximally bound 19.2 nmol of [3H]S-145/mg protein with a Kd of 29.8 nM. The [3H]S-145 binding to the purified receptor was specifically displaced by several thromboxane A2/prostaglandin H2 analogues.

Endothelium-dependent contractions induced by angiotensin I and angiotensin II in canine cerebral artery

Whether angiotensin I and angiotensin II caused endothelium-dependent contraction was examined in canine cerebral arteries. In endothelium-intact preparations, angiotensin I and angiotensin II at 10(-8) to 10(-6) M caused dose-dependent contractions, whereas both angiotensins caused much less contractions in endothelium-removed preparations. The contractions induced by angiotensin I and angiotensin II were strongly attenuated by aspirin (cyclooxygenase inhibitor) (5 x 10(-5) M), OKY-046 [thromboxane (TX) A2 synthetase inhibitor] (10(-5) M) and ONO-3708 (TX)A2 antagonist) (5 X 10(-9) M). Captopril (10(-6) M) significantly attenuated the contractions induced by angiotensin I but not those induced by angiotensin II. Angiotensin I- and angiotensin II- induced contractions were inhibited markedly by Sar1, Ala8-angiotensin II (10(-9) and 10(-8) M). The present experiments demonstrate that angiotensin I and angiotensin II produce endothelium-dependent contraction in canine cerebral artery via a factor which appears to be TXA2. Angiotensin I may be converted by endothelial cells to angiotensin II, which may activate the cells to produce TXA2 in canine cerebral artery.

cDNA cloning of Gb, the substrate for botulinum ADP-ribosyltransferase from bovine adrenal gland and its identification as a rho gene product

A 1.5 kilobase cDNA coding for the complete amino acid sequence of Gb, the substrate for ADP-ribosyltransferase in C1 and D botulinum toxins from bovine adrenal gland, has been isolated from a cDNA library of bovine adrenal gland. This cDNA encodes a polypeptide of 21,770 Da consisting of 193 amino acid residues, and the deduced amino acid sequence contains all the partial amino acid sequences reported previously (Narumiya, S., Sekine, A., and Fujiwara, M. (1988) J. Biol. Chem., 263, 17255-17257). Sequence comparison revealed that Gb is identical with the product of human rho clone 12 (rho A). The present results also confirmed our suggestion that the ADP-ribosylation occurs at Asn41 in the putative effector domain of the rho gene product.

Effects of gallamine on the contractile response of the stomach in cats

Stimulation of the vagal trunk in cats anesthetized with pentobarbital sodium produced a contractile response of the stomach during stimulation (initial contraction). Pretreatment with either hexamethonium (0.3 to 30 mg/kg, i.v.) or gallamine (1 to 100 mg/kg, i.v.) dose-dependently produced a delayed contraction, following the initial contraction after stimulation. After the administration of either hexamethonium or gallamine produced a maximum delayed contraction, then an additional dose of gallamine or hexamethonium was administered. The subsequent treatment further augmented the delayed contraction. The results indicate that gallamine induced the delayed contraction by a mechanism different from hexamethonium.

A simple and sensitive determination for plasmalogen lysophosphatidylethanolamine in rabbit platelets

Plasmalogen lysophosphatidylethanolamine (LPE) in rabbit platelets was quantitatively determined as glycero-3-phosphorylethanolamine (GPE) after treatment with 5% trichloroacetic acid at 20 degrees C for two hours. GPE was measured directly using a high performance liquid chromatography with monitoring the fluorescence of o-phthaldialdehyde/2-mercaptoethanol adducts. The assay was sensitive to 50 pmol of plasmalogen LPE and was linear over a 200-fold concentration range. While, 1-acyl LPE and phosphatidylethanolamine from bovine brain (containing about 50% plasmalogen) were hardly cleaved to GPE under the same conditions. These procedures were specific for plasmalogen LPE, and simpler and more sensitive in comparison with conventional analytical methods, e.g., two-dimensional thin layer chromatography with subsequent phosphorus assay. Employing the present method, plasmalogen LPE was found to increase rapidly and to decrease subsequently when rabbit platelets were stimulated by thrombin.

Histologic studies on the hepatic lesions induced by graft-versus-host reaction in MHC class II disparate hosts compared with primary biliary cirrhosis

By light and electron microscopic examinations, histologic changes in the liver of mice with graft-versus-host reaction (GVHR) were analyzed. To induce GVHR, C57BL/6 (B6) spleen cells were injected into (B6Xbm1)F1, (B6Xbm12)F1, and (bm1Xbm12)F1 mice. In (B6Xbm12)F1 recipient mice, bile duct changes resembling chronic non-suppurative destructive cholangitis (CNSDC) and a formation of epithelioid granulomas were observed during the course of GVHR. An epithelioid granuloma in the liver of (B6Xbm1)F1 or (bm1.Xbm12)F1 recipients was not detected. By electron microscopy, the bile duct epithelia were seen to be in close contact with infiltrating cells, and marked alterations of their cytoplasm and microvilli were demonstrated; ie, vacuolation of the cytoplasm, deterioration of microvilli, and bleb formation were frequently observed in the liver of class II-disparate hosts. Concerning the basement membrane, no marked changes characteristic of primary biliary cirrhosis (PBC), such as many-layered basement membranes containing osmium positive substance, were detected. Because the major histocompatibility complex (MHC) class II-disparate system was used in our experimental system in the GVHR, the antigen expressed on the bile duct might be a target and be associated with the formation of the initial hepatic lesions in PBC such as CNSDC and epithelioid granuloma formation. Thus, GVHR across the MHC class II antigen is believed to play an important role in the development of PBC.

Alpha-adrenoceptors in human and animal cerebral arteries: alterations after sympathetic denervation and subarachnoid hemorrhage

Vasospasm of cerebral arteries in patients with subarachnoid hemorrhage frequently presents severe clinical problems resulting from cerebral ischemia, but the pathogenesis of vasospasm is still poorly understood. The contractile response of human cerebral arteries to noradrenaline is larger than the responses in other species. Neurogenic factors controlling brain circulation may play an important role in pathological conditions such as subarachnoid hemorrhage. Motohatsu Fujiwara and colleagues review species variations of alpha-adrenoceptors in cerebral arteries and their alterations after surgical sympathectomy. They compare these changes to those occurring in human cerebral arteries following subarachnoid hemorrhage and discuss their relationship to vasospasm.

[An approach of in vivo measurement for ultrasonic myocardial tissue characterization]

The purpose of this study is to characterize regional myocardial alternations of reflected ultrasound throughout a cardiac cycle in normal and ischemic myocardium. Integrated ultrasonic backscatter (2-5 MHz) gated R wave of ECG was measured at the base, middle and apex in 4 dogs, and the apex before and after ischemia in other 4 dogs. Quantitative ultrasonic backscatter (IB) was reflected to a steel reflector. At the apex and middle, where a cyclic pattern of IB was discernible, maximum values were recorded near end diastole and minimum near end systole. The amplitude of the variation of IB throughout a cardiac cycle for each region increase progressively from base to middle to apex. Time-averaged IB over a cardiac cycle (averaged IB) was similar for each area of the heart (base = -50.6 +/- 0.5 dB (mean +/- SE), middle -49.4 +/- 0.5 dB, apex -49.7 +/- 0.6 dB. p = NS for comparison of any two regions). After occluding left anterior descending coronary artery for 30 minutes, the variation of IB was markedly blunted and averaged IB increased significantly (-47.5 +/- 0.5 dB. p less than 0.01 compared with preocclusion (-50.8 +/- 0.5 dB]. These results suggested that IB and averaged IB may permit assessment of intrinsic geometrical changes throughout a cardiac cycle (contractile properties) and histological changes respectively.

Effects of oxygen depletion on norepinephrine- and carbachol-stimulated phosphoinositide turnover in rat brain slices

We examined the effects of in vitro anoxia and in vivo hypoxia (8% O2/92% N2) on norepinephrine (NE)- and carbachol-stimulated phosphoinositide (PI) turnover in rat brain slices. The formation of 3H-labeled polyPI in cortical slices was impaired by in vitro anoxia and fully restored by reoxygenation. Accumulation of 3H-labeled myo-inositol phosphates (3H-IPs) stimulated by 10(-5) M NE was significantly reduced by anoxia (control at 60 min, 1,217 +/- 86 cpm/mg of protein; anoxia for 60 min, 651 +/- 82 cpm/mg; mean +/- SEM; n = 5; p less than 0.01), and reoxygenation following anoxia resulted in overshooting of the accumulation (control at 120 min, 1,302 +/- 70 cpm/mg; anoxia for 50 min plus oxygenation for 70 min, 1,790 +/- 126 cpm/mg; n = 5; p less than 0.01). The underlying mechanisms for the two phenomena--the decrease caused by anoxia and the overshooting caused by reoxygenation following anoxia--seemed to be completely different because of the following observations. (a) Although the suppression of NE-stimulated accumulation at low O2 tensions was also observed in Ca2+-free medium, the overshooting in response to reoxygenation was not. (b) Carbachol-stimulated accumulation was significantly reduced by anoxia and was restored by reoxygenation only to control levels. Thus, the postanoxic overshooting in accumulation of 3H-IPs seems to be a specific response to NE. (c) The decrease observed at low O2 tensions was due to a decrease in Emax value, whereas the postanoxic overshooting was due to a decrease in EC50 value.(ABSTRACT TRUNCATED AT 250 WORDS)

Is the augmentation of K+-evoked intrasynaptosomal Ca2+ concentration due to the influx of Ca2+ in rat brain synaptosomes?

Intraterminal free Ca2+ concentration modulates the subsequent release of neurotransmitters. Depolarization of synaptosomes with 29 mM K+ augments cytosolic free Ca2+ concentration, which is triphasic, the peak times being at 10, 60, and 180 s. We examined the characteristics of each elevation of cytosolic free Ca2+ concentration in rat brain synaptosomes which had been preincubated for 3 min with a Ca2+-channel blocker, such as La3+, diltiazem, nifedipine, or verapamil, and under conditions of hypoxia or acidosis. The concentration of free Ca2+ in the quin-2-loaded rat brain synaptosomes was detected fluorometrically. All these elevations were suppressed in the presence of 200 microM EGTA or 100 microM La3+. At the first phase, the elevation of cytosolic free Ca2+ concentration with high K+ stimuli was significantly inhibited by La3+ (20 microM) or by acidosis (pH 6.7). On the other hand, diltiazem, which is a more potent blocker of the release of Ca2+ from the mitochondria, inhibited the increasing cytosolic free Ca2+ concentration at the third phase in a concentration-dependent manner. Hypoxia also showed inhibition at the third phase. These results suggest that the augmentation of high K+-evoked cytosolic free Ca2+ concentration may be due to the influx of extracellular Ca2+. The increase in cytosolic free Ca2+ concentration at the third phase is no doubt linked to the mitochondrial function.

Delta 9-tetrahydrocannabinol facilitates striatal dopaminergic transmission

We examined the effects of delta 9-tetrahydrocannabinol (THC) on striatal dopaminergic neurons in rats. THC inhibited the uptake of 3H-dopamine (DA) into striatal synaptosomes. THC facilitated the release of endogenous DA but not dihydroxyphenylacetic acid (DOPAC) from striatal slices. The concentration of DA in the dorsolateral striatum was reduced by THC. We propose that THC may stimulate nigrostriatal dopaminergic neurotransmission mainly by inhibiting uptake of DA and by facilitating release of DA.

[Red cell hypoplasia following autoimmune hemolytic anemia associated with T-CLL: report of a case and review of the literature]

A 78-year-old woman, who had axillary lymphadenopathy but no hepatosplenomegaly, was admitted because of lymphocytosis. The leukocyte count was 18.1 x 10(9)/l with 72% abnormal cells. Neither anemia nor thrombocytopenia was present. Many abnormal cells and erythroblasts were seen in the bone marrow. These abnormal cells had irregular nuclei but no granules in the cytoplasm. The surface markers of these cells were positive for E-rosette, CD 2, CD 3, and Leu 7 but negative for CD 4, CD 8, CD 11 (OKM 1), CD 16 (Leu 11), and HLA-DR. The DNA analysis revealed the rearrangement of T-cell receptor beta-chain genes. Direct Coombs test was positive and red-cell life-span (51Cr) was T 1/2 = 19.5 days. The patient was diagnosed as having T-CLL with mild autoimmune hemolysis and was followed without treatment. Seven months later, the leukemia cells of peripheral blood increased to 62.6 X 10(9)/l and the frank autoimmune hemolytic anemia developed. After prednisolone, vincristine and cyclophosphamide were administered, leukemia cells of blood decreased. Anemia with reticulocytopenia, however, persisted and direct Coombs test became negative. In the bone marrow at that time, many neutrophils and megakaryocytes besides leukemia cells were preserved, but erythroblasts were hardly seen, namely a pattern of red cell hypoplasia was observed. The patient deteriorated rapidly and died 26 months after initial recognition of lymphocytosis. When complement was added, the patient's serum obtained during red cell hypoplasia but not during autoimmune hemolysis inhibited BFU-E and CFU-GM in in vitro colony assays. This case indicates that not only B-CLL but also T-CLL is accompanied by immune hematocytopenia.