Limiting-dilution analysis of the frequency of myelin basic protein-reactive T cells in Lewis, PVG/c and BN rats. Implication for susceptibility to autoimmune encephalomyelitis

Susceptibility to experimental autoimmune encephalomyelitis (EAE), which is an autoimmune disease inducible by immunization with a brain-specific antigen in complete Freund's adjuvant (CFA), is different among strains. In an attempt to resolve the immune mechanisms by which the difference in susceptibility to EAE is regulated, we re-estimated susceptibility of several strains of rats, and the frequency of antigen-reactive T cells in each strain was determined by limiting-dilution analysis. EAE was induced in Lewis (LEW), PVG/c and BN rats using four different methods: (i) active immunization with guinea-pig myelin basic protein (GPBP) in CFA; (ii) immunization with GPBP in CFA that had been further supplemented with Mycobacterium tuberculosis H37Ra (supplemented CFA); (iii) adoptive transfer of GPBP-activated spleen cells into syngeneic rats; and (iv) transfer of a GPBP-specific T-cell line. The LEW strain was susceptible to all four methods. The PVG/c strain was resistant to immunization with GPBP in conventional CFA (GPBP/conv. CFA), but was susceptible to immunization with GPBP in supplemented CFA (GPBP/suppl. CFA) and to transfer of activated spleen cells. The BN strain was resistant to all methods. Limiting-dilution analysis using T cells from LEW, PVG/c or BN rats has revealed that each strain of rat displays a different pattern of frequencies of GPBP-reactive or the 68-88 sequence (GP68-88)-reactive T cells. LEW rats showed relatively high frequencies of GPBP-reactive and GP68-88-reactive T cells after immunization with either GPBP/conv. CFA or GPBP/suppl. CFA, symptomatic rats showing higher values than asymptomatic rats. In asymptomatic PVG/c rats, the frequency of GP68-88-reactive T cells was lower than that of GPBP-reactive T cells. In PVG/c rats with clinical EAE, however, GP68-88-reactive T cells increased in frequency and were almost the same as GPBP-reactive T cells. BN rats, on the other hand, responded very poorly not only to the GP68-88 sequence but also to the whole GPBP molecule, even after immunization with GPBP/suppl. CFA. These findings, obtained by limiting-dilution analysis, strongly suggest that the development of EAE in LEW, PVG/c and BN rats is closely related to the frequency of GPBP-reactive T cells. Furthermore, it is shown that resistance to EAE found in PVG/c and BN rats may be generated by different immune mechanisms.

Cooking losses of thiamin in food and its nutritional significance

To clarify the discrepancy between values of thiamin intake reported in national nutrition survey in Japan and judgment which was concluded by medical and biochemical examination in our field survey, thiamin of various daily foods were analyzed pre and post cooking in the various cooking methods, the following results were obtained. (1) The thiamin contents in cooked daily meals were 50-60 percent of the calculated values on an average. (2) The cooking losses of thiamin were particularly large in rice and green vegetables. (3) The loss of thiamin largest in boiling, followed by baking, parching and frying. (4) High temperature, pH, and chlorine on the public water accelerated thiamin losses. (5) The decrease of thiamin in cooked foods is caused by both of getting away of thiamin from foods and cleavage of thiamin of foods.

Changes in signal transduction in Alzheimer's disease

We studied the signal transduction system including the receptor and protein kinase C (PKC) in Alzheimer's disease (AD) brains. We used 3H-TCP as a ligand for the NMDA receptor-ion channel complex. The total concentrations of 3H-TCP binding sites were significantly reduced in AD frontal cortex. 3H-TCP binding sites spared in AD brains retained the affinity for the ligand and the reactivity to NMDA, L-glutamate, and glycine. We utilized antibodies to assess the degree of involvement of different PKC isoforms in AD. The concentration of PKC (beta II) was lower in AD particulate fractions and higher in AD cytosol fractions. Immunocytochemical studies revealed reduced numbers of anti-PKC (beta II)-immunopositive neurons. Anti-PKC (alpha) faintly stained entire plaques and surrounding glial cells. Anti-PKC (beta I) stained dystrophic plaque neurites. Anti-PKC (beta II) stained the amyloid-containing portions of plaques. These results suggest an involvement of second messenger cascades in the pathogenesis of AD in addition to neurotransmitters and their receptors.

The effect of salazosulfapyridine on the in vitro antibody production in murine spleen cells

The effect of salazosulfapyridine (SASP) on the antibody response of murine spleen cells in vitro was studied. SASP inhibited the response to sheep red blood cells (SRBC), a T-cell-dependent (TD) antigen, dose-dependently and was most effective at a dose of 2 x 10(-4) M without cell toxicity. No remarkable inhibition was seen with the main metabolites of SASP, 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP). SASP failed to inhibit antibody production to T-cell-independent antigens such as dinitrophenyl-Ficoll or trinitrophenyl (TNP)-lipopolysaccharides, although the response to TNP-keyhole limpet hemocyanin, another TD antigen like SRBC, was inhibited. Further, this drug did not show any depression of the anti-SRBC plaque-forming cell (PFC) response in spleen cells treated with anti-Thy1.2 antibody plus complement. The inhibition of anti-SRBC PFC response by SASP was accompanied by a reduction of interleukin 2 (IL-2) secretion. Our results suggest that SASP may act on T cell populations and may inhibit the T-cell-dependent antibody response partly through a depression of IL-2 production. The active compound appears to be SASP itself, rather than its metabolites.

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.