Stimulation of platelet-activating factor synthesis by neurotransmitters in salivary glands

Platelet-activating factor (PAF), a phospholipid mediator exhibiting potent biological activities, has been shown to stimulate amylase release from the pancreas and salivary glands. The capacity of salivary glands for PAF biosynthesis in response to stimulation has also been demonstrated. To elucidate the role of PAF in salivary glands, we studied the regulation of platelet-activating factor synthesis by the autonomic nervous system in canine salivary glands. Acetylcholine and ionomycin stimulated PAF production in dispersed cells from parotid, submandibular, and sublingual glands of dogs. Norepinephrine and phenylephrine, but not isoproterenol, also stimulated PAF production in submandibular gland cells. Norepinephrine-induced PAF production was blocked by phentolamine but not by propranolol. Acetylcholine and norepinephrine increased both the PAF production and liberation of [14C]arachidonic acid from cells pre-labeled with [14C]arachidonic acid in the presence of Ca2+ in the medium. These stimulants increased [14C]arachidonic acid liberation without the accompanying production of PAF in Ca(2+)-deprived medium. No activators or inhibitors of protein kinase C produced or affected acetylcholine-induced PAF production. Lyso-PAF:acetyl-CoA acetyltransferase was activated in the cells treated with acetylcholine, norepinephrine, isoproterenol, and 8Br-cyclic AMP. Deprivation of Ca2+ in the medium markedly reduced acetylcholine-induced activation of the transferase, but little affected norepinephrine-, isoproterenol-, and 8Br-cyclic AMP-induced activation. Dithiothreitol-insensitive cholinephosphotransferase activity was also increased by acetylcholine, norepinephrine, isoproterenol, and 8Br-cyclic AMP, and the deprivation of Ca2+ in the medium further increased the activation of the enzyme activity by these agents. These results suggest that PAF synthesis in canine salivary glands is under the control of muscarinic cholinergic and alpha-adrenergic systems via Ca(2+)-dependent remodeling pathways, and that the independent activation of either phospholipase A2 or acetyltransferase is insufficient for PAF production in submandibular gland cells, i.e., the concurrent activation of these enzymes is required.

Cellular and molecular aspects of monoamine neurotransmitter transporters

Neurotransmitter transporters terminate synaptic neurotransmission by accumulating neurotransmitters once again after release in a sodium- and chloride-dependent fashion. The availability of the cloned neurotransmitter transporters has allowed investigation into the roles of these transporters in neuronal function. Molecular biological and protein engineering studies including in vitro site-directed mutagenesis, chimera formation of several transporter clones, or epitope-tagging various regions of transporter proteins, have revealed the topology and functionally mapped the transporter proteins. Monoamine neurotransmitter transporters such as those for dopamine, norepinephrine and serotonin are of interest, since they are a target of drugs of abuse and are involved in neuronal disorders including Parkinson's disease and depression. Therefore, elucidating the molecular basis of these transporters may clarify these problems and help develop treatments with which to combat these disorders and drug abuse.

Cocaine inhibits the release of MPP+ but not dopamine through the rat dopamine transporter

Transporter-mediated release of dopamine and the parkinsonism-inducing neurotoxin 1-methyl-4-phenylpyridinium (MPP+) was examined in COS cells, a cell line derived from monkey kidney, expressing the rat dopamine transporter. The release of preloaded [3H]MPP+ but not [3H]dopamine was dose-dependently inhibited by cocaine and other compounds known as dopamine uptake inhibitor, 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)-piperazine (GBR12,935) and nomifensine, although the uptake of both [3H]dopamine and [3H]MPP+ was sensitive to these compounds. The different sensitivity of the outward transport of dopamine and MPP+ to the uptake inhibitors might provide a clue to the identity of the specific site(s) for cocaine on the transporter.

Ca2+ entry induced by calcium influx factor and its regulation by protein kinase C in rabbit neutrophils

Extracellular application of acid extract from platelet-activating factor- or thapsigargin-treated rabbit neutrophils induced a rise of cytosolic free calcium concentration ([Ca2+]i) in neutrophils and adrenal chromaffin cells suspended in Ca(2+)-containing, but not in Ca(2+)-deficient, medium. The ability of the extract to selectively induce Ca2+ entry was also confirmed by the increase in 45Ca2+ uptake and failure to stimulate Ca2+ release in digitonin-permeabilized neutrophils. 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibited the extract-induced [Ca2+]i rise in a staurosporine (ST)-sensitive fashion, neither of which had any effect on its production. SK&F 96365 and econazole also reduced extract-induced Ca2+ entry. These results suggest that a Ca2+ entry-inducible substrate (calcium influx factor) is extracted from Ca2+ store-depleted neutrophils, and that its action may be regulated by protein kinase C and certain pharmacological agents.

Role of cytokines in leukemic type growth of myelodysplastic CD34+ cells

The clonal growth of progenitor cells from myelodysplastic syndromes (MDS) can be subdivided into four growth patterns: (1) normal, (2) no growth or low plating efficiency, (3) low colony and high cluster number, and (4) normal or high colony number with a large number of clusters. The former two (1 and 2) can be referred to as nonleukemic patterns and latter two (3 and 4) as leukemic. In a search for a role for cytokines in leukemic-type growth of MDS progenitor cells, marrow CD34+ cells were purified up to 94% for 8 normal individuals and 88% for 12 MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). The purified CD34+ cells were cultured for 14 days with various combinations of cytokines, including recombinant human macrophage colony-stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte-macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3), and stem cell factor (SCF; a ligand for c-kit) in serum-free medium. The clonal growth of MDS CD34+ cells supported by a combination of all of the above cytokines was subdivided into the two patterns of leukemic or nonleukemic, and then the role of individual or combined cytokines in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. Evidence we obtained showed that SCF plays a central role in the leukemic-type growth of MDS CD34+ cells and that G-CSF, GM-CSF; and/or IL-3 synergize with SCF to increase undifferentiated blast cell colonies and clusters over that seen in normal CD34+ cells. SCF is present in either normal or MDS plasma at a level of nanograms per milliliter, and this physiologic concentration of SCF can stimulate progenitor cells. This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blast cells. This depends, at least in part, on cytokines such as G-CSF, GM-CSF, IL-3, and SCF.

Uptake and release of dopamine through the rat dopamine transporter expressed in Xenopus laevis oocyte: evaluation by voltammetric measurement of intracellular dopamine concentration

An attempt was made to evaluate the uptake and release of dopamine (DA) through the rat dopamine transporter (DAT) expressed in Xenopus laevis oocytes. A carbon electrode was placed intracellularly into the oocyte to measure directly the intracellular concentration of DA ([DA]i) by voltammetric analyzer. Oocytes injected with the rat DAT cRNA showed a rapid rise and fall of [DA]i in response to the perfusion solution in the presence and absence of DA. In the control experiment, oocytes injected with water showed no response to external DA. An increase in [DA]i which was induced in control oocytes injected with DA into cytosol was not affected by DA-free perfusion solution, suggesting that in the absence of the transporter the accumulated DA never leaked out from the cell. Thus, the bi-directional DA fluxes through the transporter were demonstrated electrochemically in real time on-line mode.

Changes in cellular proteins of Deinococcus radiodurans following gamma-irradiation

In order to examine radiation-induced proteins in an extremely radioresistant bacterium, Deinococcus radiodurans R1, changes in cellular proteins after gamma-irradiation were analysed by two-dimensional gel electrophoresis and silver staining. Nine proteins (190, 120, 87,60, 58, 52, 46, 41 and 41 kDa) were increased (or appeared) and more than 13 proteins diminished after gamma-irradiation at 6 kGy. Increase of eight proteins (except for 190-kDa protein) was prevented when the cells were irradiated in the presence of chloramphenicol. Three proteins, 87, 60 and 46 kDa, continued to be synthesized during post-irradiation incubation, and the amounts of these proteins increased with higher doses in a range of 1-12 kGy. Changes in the amount of proteins after irradiation in the R1 strain were compared with those in a moderately radioresistant mutant (rec I) and in a highly radiosensitive mutant (rec30). These three proteins were increased in both R1 and recI, but not in rec 30, suggesting that they are characteristic for radioresistant strains. In addition, from the microsequence analysis, the 46-kDa protein was found to be homologous to the EF-Tu protein of Escherichia coli, whereas the remarkable homologous sequence to the N-terminal of the 60-kDa protein was not found among the known proteins.

[Experimental study on effects of a high-sugar diet and physical exercise on serum phospholipids in young adults]

The life style of young adults has been receiving attention with a view to its improvement to prevent coronary heart diseases (CHD) later in life. In this study, to determining the influence of different life styles on the serum phospholipids level, we carried out experimental studies on the effects a high sugar diet and physical exercise on serum phospholipid levels. Considering the trend for young people to consume large quantities of carbonated drinks, in which most of the sugar is sucrose, we tested the effect of a high carbohydrate diet on one group of six healthy male subjects and did not find that it caused a significant increase in the serum phospholipids level. In another group of 108 healthy young female subjects, a mild exercise regimen results in a slight, but significant decrease in the serum phospholipid level (p < 0.01). The serum total cholesterol level of the group did not exhibit a significant change.

Changes in hepatic enzyme activities related to ethanol metabolism in mice following chronic ethanol administration

Male mice of three strains, C57BL, DBA and C3H/He, were fed on commercial food with 10% (v/v) ethanol solution as drinking liquid ad libitum for eighty days, and the changes in the activities of enzymes in the metabolic pathway of ethanol in the liver were examined. C57BL and C3H/He mice showed a preference for drinking the 10% (v/v) ethanol solution, while DBA mice did not. The ethanol intake g/g of body weight of C3H/He mice showed the highest value among all three strains and that of C57BL mice tended to show higher value than that of DBA mice. The liver weights of C57BL and C3H/He mice increased significantly following chronic ethanol administration, but that of DBA did not. The cytosolic enzyme alcohol dehydrogenase (ADH) showed no changes in any of the strains following chronic ethanol administration. The microsomal ethanol-oxidizing system (MEOS) of C57BL mice exhibited approximately 2-fold higher activity compared to that of DBA and C3H/He mice but did not increase in any strain following chronic ethanol administration. However, the microsomal aniline hydroxylase activity in the liver increased significantly in C57BL and C3H/He mice following chronic administration of ethanol. The microsomal cytochrome P-450 content also tended to slightly increase in the same strains of mice. It seemed that cytochrome P-450IIE1 was induced in the liver microsomes of these strains. Total aldehyde dehydrogenase (ALDH) activities together with high-Km ALDH activity increased markedly in the microsomes of C57BL mice and tended to increase in C3H/He mice, while it did not change in DBA mice following chronic ethanol administration. In the mitochondria of C57BL, total ALDH activities increased slightly and high-Km ALDH activities tended to increase. These mitochondrial ALDH activities of C3H/He and DBA mice tended to increase following chronic ethanol administration. The cytosolic ALDH activity showed no changes in any strain of mice following chronic ethanol administration. It seemed that in the microsomes, the activities of enzymes related to oxidation of ethanol increased in C57BL and C3H/He mice, which tended to consume a large amount of ethanol, and did not in DBA mice which tended to consume a small amount of it. It seemed that the increases in activities of enzymes related to oxidation of acetaldehyde in the microsomes and in the mitochondria were responsible for the strain difference.

Effect of balloon occluded arterial infusion of anticancer drugs on the prognosis of cervical cancer treated with radiation therapy

PURPOSE

The effect of local injection of anticancer drugs by balloon catheter, i.e., balloon occluded arterial infusion (BOAI), on the prognosis of cervical cancer treated with radiotherapy were retrospectively estimated.

METHODS AND MATERIALS

Sixty-five patients with cervical cancer (Stage I-IV) treated by irradiation were included in the study. Among the 65 cases, 2 were in Stage I, 13 in Stage II, 40 in Stage III, and 10 in Stage IV. Patients who received surgical resection were excluded. Thirty-nine patients received BOAI and 44 received brachytherapy. Twenty-six patients were not indicated for BOAI because of insufficient renal function, hepatic complications, hematological complications, and refusal from the patients. Cisplatin (0.9-1.7 mg/kg), Adriamycin (0.7-0.9 mg/kg), and Pepleomycin (0.4-0.6 mg/kg) were administered simultaneously into the bilateral internal iliac arteries by BOAI. External irradiation was given by 10 MV x-ray. Total dose administered to the regional lymph nodes by the external irradiation was 48.3 +/- 8.7 Gy. Radium was used at brachytherapy. The dose delivered by the brachytherapy at point A was 45.3 +/- 14.9 Gy. Patients without brachytherapy received 26.1 +/- 19.1 Gy of boost irradiation by the external photon beam. The survival probabilities of the patients were calculated by Kaplan-Meier method.

RESULTS

The 5-year survival rates of the Stage III patients with and without BOAI were 53 +/- 13% and 24 +/- 18%, respectively (p = 0.036). By multivariate analyses using Cox's proportional hazard model, stage and BOAI were selected as significant predictors of the prognosis. Transient bone marrow suppression was observed in about half of the patients with BOAI. No significant increase of the incidence of the late radiation damage by BOAI in rectum or in urinary bladder was observed.

CONCLUSION

Balloon occluded arterial infusion of anticancer drugs may improve the prognosis of the patients with cervical cancer without increasing the incidence of the late radiation damage. A larger scale prospective randomized study is desired.

Effect of nicotine on dopamine uptake in COS cells possessing the rat dopamine transporter and in PC12 cells

The effect of nicotine on the uptake of dopamine (DA) is not completely understood. We studied its effect on PC12 cells and on COS cells transfected with the rat DA transporter cDNA (pcDNADAT1). DA uptake by PC12 cells was inhibited by nicotine in a concentration-related fashion. Treatment of PC12 cells with nerve growth factor (NGF) increased such inhibition. This inhibitory effect was abolished by hexamethonium and mecamylamine, indicating that nicotine acted via the nicotinic acetylcholine (nACh) receptors in PC12 cells. This view is also supported by evidence that acetylcholine (ACh) reduced the uptake of DA in a hexamethonium-, but not atropine-, sensitive fashion. However, nicotine failed to inhibit DA uptake by COS cells possessing the DA transporter. These results suggest that the inhibitory effect of nicotine on DA uptake, when coupled with an nACh receptor leading to an indirect action on the transporter, may play a role in regulating extracellular concentrations of DA.

Pharmacological evidence for the possible involvement of repetitive action potentials in facilitation by GABA of catecholamine secretion in bovine adrenal chromaffin cells

1. gamma-Aminobutyric acid (GABA) evokes catecholamine (CA) secretion and enhances the stimulation-evoked CA secretion via facilitation of Ca2+ entry in a Cl(-)-dependent manner. The present study was designed to investigate further the ionic mechanism of modulation by GABA of CA secretion from adrenal medulla, using a primary culture of bovine chromaffin cells. 2. Tetrodotoxin (TTX), a voltage-sensitive Na+ channel blocker, reduced GABA-evoked CA secretion. 3. Inhibition of the sodium pump by ouabain or removal of extracellular K+ enhanced GABA-evoked CA secretion in a TTX-sensitive manner. 4. Tetraethylammonium (TEA) and cesium, which are known to block some types of K+ channels, markedly enhanced GABA-evoked CA secretion in a concentration-related fashion. TEA-induced enhancement of the GABA-evoked CA secretion was attenuated by TTX or replacement of extracellular Na+ by choline. On the other hand, ouabain accelerated the effect of TEA. 5. TEA and ouabain also enhanced GABA-induced Ca2+ influx and accumulation of cytosolic Ca2+, assessed with 45Ca2+ uptake and quin2 fluorescence. 6. Veratridine increased accumulation of cytosolic Ca2+ in a TTX-sensitive manner. GABA facilitated the veratridine-induced elevation of cytosolic Ca2+ even when the GABA-induced rise of cytosolic Ca2+ levelled off. 7. These results suggest the involvement of repetitive action potentials in modulation of GABA by Ca2+ mobilization and, as a consequence, of the CA secretion in chromaffin cells.

Regulation by protein kinase C of platelet-activating factor- and thapsigargin-induced calcium entry in rabbit neutrophils

12-O-Tetradecanoylphorbol-13-acetate (TPA) time-dependently inhibited the platelet-activating factor (PAF)-induced rise in cytosolic free calcium concentration ([Ca2+]i) in rabbit neutrophils, whereas staurosporine significantly enhanced it. Inositol 1,4,5-trisphosphate (IP3) induced Ca2+ release in digitonin-permeabilized cells but not in PAF-pretreated permeabilized cells. IP3-induced Ca2+ release was not affected by protein kinase C activators or inhibitors. In the cells pretreated with PAF and thapsigargin in Ca(2+)-deficient medium, stimulated Ca2+ entry was evoked by the subsequent addition of CaCl2. TPA inhibited the Ca2+ entry induced by PAF and thapsigargin in a staurosporine-reversible manner but not thapsigargin-induced [Ca2+]i elevation. These results suggest that protein kinase C negatively regulates PAF- and thapsigargin-induced rise in [Ca2+]i possibly by inhibiting Ca2+ store depletion-induced Ca2+ entry.

Phorbol esters alter functions of the expressed dopamine transporter

Recent elucidation of the amino acid sequences of the neurotransmitter transporters reveals several consensus sequences for phosphorylation by kinases including protein kinase C. Protein kinase C activation did modulate the function of the rat dopamine transporter expressed in COS cells. Cell treatment with the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) reduced the affinity of binding of the radiolabeled cocaine analog [3H](-)-2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (WIN 35,428) without affecting its Bmax. The uptake of [3H]dopamine was reduced by treatment with PMA in a staurosporine-sensitive manner. Kinetic analysis revealed that the inhibitory effect of PMA on [3H]dopamine uptake was due to reduced uptake velocity and a small reduction of affinity for Na+, without changed affinity for dopamine. 1-Oleoyl-2-acetyl-sn-glycerol (OAG) mimicked these actions of PMA. These results demonstrate that activation of protein kinase C alters dopamine transporter functions in both ligand recognition and substrate translocation. These phosphorylation phenomena in vitro suggest the possibility that phosphorylation could modulate the activity of this important dopaminergic synaptic regulator under physiological conditions.

Plasmids in several strains of Deinococcus radiodurans

Deinococcus radiodurans is known as a radioresistant bacterium. For the construction of the shuttle vector, plasmids of this bacterium were isolated and investigated. At least two new plasmids in the cells of D. radiodurans MR1, KR1 and Sark were found in this experiment. However, a common plasmid among MR1, KR1 and Sark strains could not be found. These plasmids would be useful for the construction of the shuttle vector for cloning radioresistant genes of this bacterium.

Possible involvement of nitric oxide in acetylcholine-induced increase of intracellular Ca2+ concentration and catecholamine release in bovine adrenal chromaffin cells

The role of nitric oxide (NO) in neurotransmitter release was studied using bovine adrenal medullary chromaffin cells. L-Arginine and sodium nitroprusside (SNP) slightly increased the intracellular free calcium concentration ([Ca2+]i), and the effects of the agents were dependent on the presence of the extracellular Ca2+ ([Ca2+]o), but were not blocked by verapamil (30 microM) or diltiazem (30 microM). SNP enhanced the acetylcholine (ACh)-induced rise in [Ca2+]i in the presence but not in the absence of [Ca2+]o. The effects of L-arginine but not those of SNP were inhibited by N omega-nitro-L-arginine (L-NNA). L-NNA significantly reduced the ACh-induced rise in [Ca2+]i and catecholamine (CA) release, and the reduction was restored by L-arginine but not by D-arginine. These results suggest a possible involvement of NO in ACh-induced [Ca2+]i rise and CA release in bovine adrenal chromaffin cells.

Effect of 12-hydroxyeicosatetraenoic acid on cytosolic calcium in human neutrophils

12-Hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) has been reported to be a chemoattractant for human neutrophils. To assess its cellular mechanism, we focused on the effect of 12-HETE on cytosolic Ca2+ ([Ca2+]i) and characterized the effect of 12-HETE on [Ca2+]i in human neutrophils. 12(S)- and 12(R)-HETE increased [Ca2+]i in the presence and absence of extracellular Ca2+ in a concentration-related fashion. The elevation of [Ca2+]i by 12(R)-HETE was completely abolished by pertussis toxin treatment. U-73122, a selective phospholipase C inhibitor, depressed the 12(S)- and 12(R)-HETE-induced rise in [Ca2+]i in the presence and absence of extracellular Ca2+. 12(R)-HETE resulted in the rapid production of inositol 1,4,5-trisphosphate (IP3). Furthermore, 12(R)-HETE elicited slight depolarization of neutrophils as assessed using the fluorescent dye bis-oxonol. These results provide evidence demonstrating the signal transduction pathway in human neutrophils after stimulation with 12-HETE and suggest that 12-HETE causes a rapid rise of [Ca2+]i by mobilizing Ca2+ from an IP3-sensitive intracellular Ca2+ pool in human neutrophils.

[A case with AML (M4EO) accompanied by recurrent reactive histiocytosis which showed spontaneous remission]

A 30-year-old female was admitted to our hospital complaining of high fever and fatigue. Laboratory findings showed as follows; WBC 41,500/microliter (40% of blasts), Hb 8.5g/dl, platelets 4.4 x 10(4)/microliter. Cytochemical staining of blasts was positive for peroxidase and non-specific esterase with NaF inhibition. Chromosome analysis showed 46, XX, inv (16p+,q-). AML with eosinophilia was diagnosed. During myelosuppression after remission induction therapy, she developed high fever, and did not respond to transfusions. Marrow smears showed the presence of phagocytic histiocytes consisting of 18% total nuclear cells. A diagnosis of reactive histiocytosis (RH) was made. She recovered spontaneously, but suffered two episode of recurrence during subsequent chemotherapy. Reactive histiocytosis is characterized by proliferation of histiocytes which phagocyte blood cells in immunodeficient cases, e.g. a myelosuppressive state after chemotherapy. RH causes high fever and prolonged myelosuppression. It is considered to be one of the poor prognostic factors in AML during chemotherapy, and spontaneous recovery is rare. In this report, the effect of hydrocortisone on histiocytes derived from patient marrow was also investigated in vitro.

Dopamine transporter mutants selectively enhance MPP+ transport

MPP+ (1-methyl-4-phenylpyridinium), a dopaminergic neurotoxin that provides the best available experimental model of Parkinson's disease, is selectively concentrated in dopamine neurons by the dopamine transporter (DAT). DAT also serves as a primary recognition site for cocaine. To help define selective molecular mechanisms by which MPP+ uptake occurs, we have tested dopamine transporters mutated in several residues for their abilities to accumulate dopamine and MPP+, and to bind a cocaine analog. Mutants in DAT 7th and 11th hydrophobic putative transmembrane domains increase MPP+ uptake velocity and affinity (1/KD), respectively. These mutations exert much more modest effects on dopamine uptake and have little impact on cocaine analog binding. These findings provide the first example of mutations that enhance transport and identify specific DAT amino acids selectively involved in neurotoxin uptake. They may also have implications for the feasibility of developing drugs that could specifically block accumulation of Parkinsonism-inducing neurotoxins.

12-Lipoxygenase product as an inhibitor of the action of chemoattractant peptide fMet-Leu-Phe in rat neutrophils

1. 12-Hydroxyeicosatetraenoic acid (12-HETE) has been evaluated for its capacities to modulate neutrophil migration and cytosolic Ca2+ ([Ca2+]i) using compounds prepared by chemical synthesis and tissue extract from dog gingiva. 2. 12-HETE inhibited N-formyl-Met-Leu-Phe (fMLP)-stimulated neutrophil migration in a concentration-dependent fashion. 3. The tissue extract from dog gingiva mimicked the actions of 12-HETE. 4. Although 12-HETE failed to increase [Ca2+]i, preincubation of neutrophils with 12-HETE led to a suppression of [Ca2+]i when the cells were subsequently stimulated by fMLP. 5. Again tissue extract from dog gingiva mimicked the action of 12-HETE on [Ca2+]i. 6. These results suggest the possible correlation of the inhibitory activities of 12-HETE on the regulation of neutrophil migration and Ca2+ mobilization, and this may be important for the role of 12-HETE in pathogenesis in periodontal tissues.