Long-term clinical impact of serum albumin in coronary artery disease patients with preserved renal function.

BACKGROUND AND AIMS: Low serum albumin level is reportedly associated with worse clinical outcomes in patients with chronic kidney disease (CKD). However, associations between decreased serum albumin level and outcomes in non-CKD patients with coronary artery disease (CAD) remain unclear. Therefore, we aimed to evaluate the prognostic value of serum albumin concentrations in stable CAD patients with preserved renal function. METHODS AND RESULTS: We studied 1316 patients with CAD and preserved renal function (estimated glomerular filtration rate ≥60 mL/min/1.73 m2) who underwent their first PCI between 2000 and 2011 and had data available for pre-procedural serum albumin. Patients were assigned to quartiles based on pre-procedural albumin concentrations. The incidence of major adverse cardiac events (MACE), including all-cause death and non-fatal myocardial infarction, was evaluated. Mean albumin concentration was 4.1 ± 0.4 g/dL. During the median follow-up of 7.5 years, 181 events occurred (13.8%). Kaplan-Meier curves revealed that patients with decreased serum albumin concentrations showed a higher event rate for MACE (log-rank, p < 0.0001). Using the highest tertiles (>4.3 g/dL) as reference, adjusted hazard ratios were 1.97 (95% CI, 1.12-3.55), 1.77 (95% CI, 0.99-3.25), and 1.19 (95% CI, 0.68-2.15) for serum albumin concentrations of <3.9, 3.9-4.0, and 4.1-4.3 g/dL, respectively. Decreased serum albumin concentration was associated with MACE even after adjusting for other independent variables (HR, 2.21 per 1-g/dL decrease; 95% CI, 1.37-3.56, p = 0.001). CONCLUSION: Decreased serum albumin concentration independently predicted worse long-term prognosis in non-CKD patients after PCI. Pre-procedural serum albumin concentration could offer a useful predictor for patients with CAD and preserved renal function.

Testing mosses exposed in bags as biointerceptors of airborne radiocaesium after the Fukushima Dai-ichi Nuclear Power Station accident.

Eight years after the Fukushima nuclear accident, mosses exposed in bags were used to investigate their ability to accumulate radiocaesium and therefore to act as biointerceptors of 134Cs and 137Cs in the evacuated area of the Fukushima territory. Bags were filled with 3 widely studied moss species (Sphagnum palustre, Hypnum cupressiforme, and Hypnum plumaeforme) and exposed for 3, 6 or 9 weeks at 5 former residential sites within the Fukushima area and, for comparison, at three background sites located 700 km away. The radiocaesium activity concentrations found in moss bags were evaluated as function of exposure time, site conditions and moss species. In the Fukushima area, the moss bags accumulated 137Cs at all exposure sites and in all exposure periods, with S. palustre having the highest 137Cs accumulation ability. The 137Cs activity concentrations (from 28 to 4700 Bq kg-1) measured in moss bags increased with the exposure time and were consistent with the decontamination status of each exposure site, highlighting the big potential of moss bags to discriminate among exposure sites. Time dependency of 137Cs activity concentrations measured in mosses allowed the calculation of location-specific and species-specific factors, which can be used to predict radiocaesium accumulation trends in future biomonitoring surveys performed in the same area with the same experimental design. Autoradiography and electron microscopy analyses of the moss surfaces revealed a prevalence of soil-derived particulate form of radiocaesium, suggesting the use of moss bags as warning sensors of resuspended particles potentially harmful for local residents.

Hapten-induced colitis is associated with colonic patch hypertrophy and T helper cell 2-type responses.

To investigate the potential involvement of T helper (Th)2-type responses in murine models of intestinal inflammation, we used trinitrobenzene sulfonic acid (TNBS)-hapten to induce inflammatory bowel disease in situations where Th1-type responses with interferon (IFN)-gamma synthesis are either diminished or do not occur. Intracolonic administration of TNBS to either normal (IFN-gamma+/+) or Th1-deficient IFN-gamma knockout (IFN-gamma-/-) BALB/c mice resulted in significant colitis. In IFN-gamma-/- mice, crypt inflammation was more severe than in IFN-gamma+/+ mice and was accompanied by hypertrophy of colonic patches with a lymphoepithelium containing M cells and distinct B and T cell zones resembling Peyer's patches. Hapten-specific, colonic patch T cells from both mouse groups exhibited a Th2 phenotype with interleukin (IL)-4 and IL-5 production. TNBS colitis in normal mice treated with anti-IL-4 antibodies or in IL-4(-/-) mice was less severe than in either IFN-gamma+/+ or IFN-gamma-/- mice. Our findings now show that the Th2-type responses in TNBS colitis are associated with colonic patch enlargement and inflammation of the mucosal layer and may represent a model for ulcerative colitis.

Cardiac intervention using high-intensity focused ultrasound: creation of interatrial communication in beating heart of an anesthetized rabbit.

OBJECTIVE: Current fetal cardiac intervention for restrictive atrial septum is invasive and technically demanding. We investigated the feasibility of computer-assisted high-intensity focused ultrasound (HIFU) for cardiac intervention on the atrial septum of a beating heart. METHODS: To create an interatrial communication in the beating heart of nine anesthetized rabbits, the heart was exposed surgically and placed under a water-filled tank, in contact with the tank's membranous base. A HIFU transducer (3.3 MHz) coupled with a diagnostic ultrasound probe (10.0 MHz) was placed in the tank over the beating heart. The focus of the HIFU transducer was set so that it could create a hole in the target area on the atrial septum during the early diastolic phase. HIFU delivery was controlled based on ultrasound images captured with real-time image-recognition software. We attempted to create interatrial communication using HIFU and assessed the cardiac tissue specimen pathologically. RESULTS: In eight of nine rabbits, small holes in the atrial septum were successfully created. Serious complications occurred in two animals: a fatal atrioventricular block in one and a cardiac tamponade in the other. CONCLUSION: HIFU combined with a computer-assisted imaging system might be useful to create interatrial communication in beating hearts. This procedure may be helpful for making current fetal cardiac intervention less invasive.

Down-regulation of norepinephrine transporter expression on membrane surface induced by chronic administration of desipramine and the antagonism by co-administration of local anesthetics in mice.

We have previously shown that chronic administration of the antidepressant desipramine, a norepinephrine transporter (NET) inhibitor to mice markedly enhanced convulsions induced by local anesthetics and that behavioral sensitization may be relevant to decreased [(3)H]norepinephrine uptake by the isolated hippocampus. The co-administration of local anesthetics with desipramine reversed the behavioral sensitization and down-regulation of NET function induced by desipramine. The present study aimed to elucidate whether chronic treatment with desipramine regulates the expression of NET protein examined in membrane fractions in various brain regions and whether co-administration of local anesthetics affects the desipramine-induced alteration of NET expression. Desipramine with or without local anesthetics was injected intraperitoneally once a day for 5 days. The animals were decapitated 48 h after the last administration of drugs and the whole cell fraction, membrane fraction and cell-surface protein fraction were prepared. [(3)H]nisoxetine binding was significantly reduced in the P2 fraction of the hippocampus by chronic administration of desipramine, and the reduction was overcome by co-administration of lidocaine with desipramine. Immunoreactive NET was detected by SDS-PAGE and immunoblotting in the murine hippocampus. NET protein expression in the whole cell fraction and membrane fraction was not affected by treatment with any drugs. However, administration of desipramine significantly reduced the amount of immunoreactive NET in the cell-surface protein fraction. This reduction was blocked by simultaneous injection of lidocaine, bupivacaine or tricaine. These results indicate that the NET down-regulation indicated by the reduction of [(3)H]nisoxetine binding was induced by administration of desipramine via decrease of NET localization on the cell surface. The antagonistic actions of local anesthetics against NET down-regulation by desipramine were related to alterations of the cell-surface localization of NET.

Miniature bending manipulator for fetoscopic intrauterine laser therapy to treat twin-to-twin transfusion syndrome.

BACKGROUND: Recent typical therapy for twin-to-twin transfusion syndrome (TTTS) is selective laser photocoagulation of anastomotic communicating vessels on the placenta using the fetoscopic approach. The difficulty of a conventional laser device approach for this procedure depends significantly on the placental location, so a new robotized device is required to bend the direction of laser irradiation flexibly within the narrow uterus. METHODS: The authors designed a miniature bending mechanism impelled by a wire-guided linkage driving method that provides a stable procedure for bending laser irradiation from -90 degrees to 90 degrees . Using this bending mechanism, the authors developed a bending manipulator with a diameter of 3.5 mm and a hollow central channel with a diameter of 0.8 mm for passing a glass fiber for neodymium:yttrium-aluminum-garnet (Nd:YAG) laser photocoagulation. The bending mechanism is motorized by an electrical actuator and controlled by a grip-type interface with a small joystick. The robotized tip's part and the actuator's part are easily separable for cleaning and sterilization. RESULTS: In performance evaluations of the manipulator, the bending characteristics with a glass fiber were examined. The bending range was -52.6 degrees to 80 degrees, with a very small hysteresis error, and the bending repeatability error was 0.5 degrees +/- 0.2 degrees, which corresponds with the high accuracy of 0.2 +/- 0.1-mm positioning error at the glass fiber's tip. In the evaluation of Nd:YAG laser photocoagulation, the study confirmed that the manipulator performed effective laser photocoagulation of the placental phantom surface (underwater chicken liver). The large bending range, reaching 80 degrees, enabled a flexible approach from various directions with a high irradiation efficiency of no less than 96.6%. CONCLUSIONS: The authors' original miniature bending manipulator can change the laser irradiating direction with highly repeatable positioning accuracy for speedy, safe, and effective vessel occlusion in clinical practice.

Laparoscopic cholecystectomy using a newly developed laparoscope manipulator for 10 patients with cholelithiasis.

BACKGROUND: Laparoscopic surgery has continued to gain popularity in almost all fields of abdominal surgery, and robotic systems have been introduced in general surgery. Naviot is a new remote-controlled laparoscope manipulator system controlled by the operator's hand. This study assessed its introduction into clinical practice. METHODS: A group of 10 consecutive patients with cholelithiasis underwent laparoscopic cholecystectomy assisted by the Naviot system (Naviot group). Another group of 41 patients who underwent laparoscopic cholecystectomy with a conventional human camera holder (human camera group) were selected for a comparison of their operative results with those of the Naviot group. RESULTS: The operative time of 89.3 +/- 27.1 min for the Naviot group was significantly longer than that of 74.8 +/- 28.1 min for the human camera group (p < 0.05). However, when the setup time for the Naviot system was excluded, the operative time was not significantly different from that for the human camera group. Other operative results showed no significant difference between the two groups. CONCLUSIONS: The authors believe that the new Naviot system is feasible for clinical use, and that it enables surgeons to perform solo gastrointestinal surgery.

An IgG3 monoclonal antibody established after immunization with GM3 lactone: immunochemical specificity and inhibition of melanoma cell growth in vitro and in vivo.

In previous studies, an IgM monoclonal antibody (M2590), established after immunization of C57BL/6 mice with syngeneic B16 melanoma cells, was found to react with melanoma cells, but not with various normal cells and tissues (Taniguchi, M., and Wakabayashi, S., Jpn. J. Cancer Res., 75:418-426, 1984). The structure defined by this antibody was identified as GM3 (Hirabayashi, Y., et al., J. Biol. Chem., 260:13328-13333, 1985) organized in membranes at high density, although the real immunogen was suggested to be GM3 lactone (Nores, G. A., et al., J. Immunol., 139:3171-3176, 1987). Since GM3 lactone was found to be highly immunogenic, we subsequently immunized C57BL/6 mice with GM3 lactone coated on Salmonella minnesotae and established hybridoma DH2, secreting an IgG3 antibody showing preferential reactivity with GM3 lactone over GM3 under certain conditions. The reactivity of the DH2 antibody was competitively inhibited by M2590, and it showed a preferential reactivity with melanoma cells and displayed various immunochemical and immunobiological properties similar to those of M2590. However, DH2 antibody inhibited melanoma cell growth in vivo, induced antibody-dependent cytotoxicity in vitro, and showed a preferential accumulation in melanoma growth in vivo. These properties are characteristic of the IgG3 subclass, in striking contrast to IgM antibody M2590, which does not inhibit cell growth in vivo or in vitro and does not induce antibody-dependent cytotoxicity. Thus, immunization with lactone forms of tumor-associated ganglioside antigens might be useful in the production of antibodies and prevention of tumor cell growth in vivo (antitumor vaccines).

Effects of pyruvate and other metabolites on cyclic GMP levels in incubations of rat hepatocytes and kidney cortex.

Pyruvate increased cyclic GMP levels in rat hepatocytes. The effects were observed without or with 1-methyl-3-isobutylxanthine. Lactate, acetate, oxaloacetate, alpha-ketoglutarate, succinate, acetoacetate and beta-hydroxybutyrate also increased cyclic GMP levels. Some compounds increased cyclic GMP in kidney cortex slices. The effects were dependent upon Ca2+ in the medium. Cyclic AMP was increased 30-50% by some of these substances with 2.6 mM Ca2+. Rotenone, oligomycin, antimycin, dinitrophenol, KCN, and arsenate decreased GTP and ATP, basal cyclic GMP and the pyruvate effect, but did not alter cyclic AMP. Although fluoroacetate alone had no effect on cyclic nucleotides, GTP, or ATP, it potentiated the pyruvate effect on cyclic GMP. Adenosine and guanosine increased cyclic GMP and GTP to a similar extent of 30-50%. Aminooxyacetate, cycloserine, pentenoic acid and mepacrine decreased the pyruvate effect while cycloserine or mepacrine alone increased cyclic GMP. Citrate and mepacrine inhibited soluble and particulate guanylate cyclase from rat liver while cycloserine and acetoacetate increased guanylate cyclase activity. None of the other compounds altered guanylate cyclase activity. These results indicate that various metabolites and inhibitors can alter cyclic GMP accumulation in hepatocytes and renal cortex slices. Several mechanisms may be involved in these effects.

GABAA receptor-mediated increase of cytosolic Ca2+ in isolated bovine adrenal chromaffin cells.

We have studied the effects of GABA on cytosolic free Ca2+ concentration ([Ca2+]i) as a means of investigating the role of GABA in adrenal catecholamine (CA) secretion. It was demonstrated that GABA caused an elevation of [Ca2+]i via the GABAA receptor in a concentration-dependent manner, which was well correlated with an increase of 45Ca uptake, an increase of CA release and a depolarization of chromaffin cells assessed with bis-oxonol fluorescence. Since the GABA-induced rise of [Ca2+]i was absolutely dependent on the presence of extracellular Ca2+ and partly sensitive to nifedipine, at least one entry route for Ca2+ facilitated by GABA via a voltage-sensitive Ca2+ channel was suggested. When extracellular Cl- was lowered, GABA-induced CA release, depolarization, and rise of [Ca2+]i were all markedly enhanced. It is possible that GABA plays a modulatory role in the regulation of adrenal CA secretion as a facilitatory modulator.

Dihydroheptaprenyl and dihydrodecaprenyl monophosphates induce apoptosis mediated by activation of caspase-3-like protease.

Dolichyl phosphate, an essential carrier lipid in the biosynthesis of N-linked glycoprotein, has been found to induce apoptosis in rat glioma C6 cells and human monoblastic leukemia U937 cells. In the present study, dolichyl phosphate and structurally related compounds were examined regarding their apoptosis-inducing activities in U937 cells. Dihydroheptaprenyl and dihydrodecaprenyl phosphates, of which isoprene units are shorter than that of dolichyl phosphate, induced apoptosis in U937 cells. This phenomenon occurred in a dose- and time-dependent manner, as seen with dolichyl phosphate-induced apoptosis. Derivatives of the same isoprene units of dolichyl phosphate, such as dolichol, dolichal or dolichoic acid, did not induce DNA fragmentation. Farnesyl phosphate and geranylgeranyl phosphate also failed to induce apoptosis. During apoptosis, the caspase family of cysteine proteases play important roles. We observed that apoptosis induced by dihydroprenyl phosphate was mediated by caspase-3-like (CPP32-like) activation but not by caspase-1-like (ICE-like) activation. This caspase-3-like activation was inhibited by a specific inhibitor of caspase-3, DEVD-CHO, but not by an caspase-1 inhibitor YVAD-CHO. We interpret these results to mean that dihydroprenyl phosphates with more than seven isoprene units have apoptosis-inducing activity and that their signal is mediated by caspase-3-like activation.

MPP+ toxicity and plasma membrane dopamine transporter: study using cell lines expressing the wild-type and mutant rat dopamine transporters.

The Parkinsonism-inducing neurotoxin 1-methyl-4-phenylpyridinium (MPP+) causes specific cell death in dopaminergic neurons after accumulation by the dopamine transporter (DAT). COS cells, a non-neuronal cell line insensitive to high doses of MPP+, becomes sensitive to MPP+ when transfected with the rat DAT cDNA. We analyzed the bi-directional transport of MPP+ and its toxicity in several cell lines expressing wild or mutant DATs. Cell death in COS cells expressing wild DAT by exposure to MPP+ was concentration-dependent and cocaine-reversible. Increased wild DAT expression caused higher sensitivities to the toxin in HeLa cells. Although several mutant DATs demonstrated greater transport activity than the wild-type, they displayed similar or lower sensitivity to MPP+ toxicity. Reverse transport of preloaded [3H]MPP+ through DAT was facilitated in COS cells expressing certain mutant DATs, which consistently displayed less sensitivity to MPP+ toxicity. These results suggest that re-distribution of MPP+ due to influx/efflux turnover through the transporter is a key factor in MPP+ toxicity.

Biochemical bases in differentiation of a mouse cell line GSM06 to gastric surface cells.

A mouse gastric surface cell line GSM06 established from a transgenic mouse harboring temperature-sensitive simian virus 40 large T-antigen gene was subjected to the lipid and glycoprotein analysis. When GSM06 cells were cultured for a long time after formation of a confluent monolayer, they differentiated to resemble foveolar epithelial cells morphologically. Biochemical changes during culture were studied in cells harvested just when a monolayer had formed (day 0), on day 7, and on day 21. Content of total phospholipids, cholesterol, cholesterol sulfate, total sugar and sialic acid increased about 1.5-fold from day 0 to 7 and remained elevated till day 21. The fatty acid composition of phospholipids revealed increased relative levels of oleic acid in phosphatidylcholine and phosphatidylethanolamine, and an increased level of plasmenylethanolamine from day 0 to 7. The level of dolichylphosphate continued to increase in a time-dependent manner. Glycosylation of various proteins, detected with lectins, was enhanced from day 7. In addition, greater resistance to taurodeoxycholate and acetylsalicylic acid was observed on days 7 and 21 than on day 0. Thus, enhanced glycosylation of proteins and an overall increase in the area of cellular membranes were the major changes in GSM06 cells during culture, and they were accompanied by an enhancement of cytoprotective potential.

Transport of dopamine and levodopa and their interaction in COS-7 cells heterologously expressing monoamine neurotransmitter transporters and in monoaminergic cell lines PC12 and SK-N-SH.

The present study investigated the effects of levodopa, a precursor of dopamine (DA) therapeutically used for the treatment of Parkinson's disease, on DA transport in the two different systems, COS-7 cells heterologously expressing rat monoamine transporter cDNA and in monoaminergic cell lines PC12 and SK-N-SH. Levodopa enhanced uptake of [3H]DA and [3H]norepinephrine (NE) but not [3H]serotonin in the transfected COS-7 cells in a concentration-dependent manner. On the other hand, in PC12 and SK-N-SH cells where NET is functionally expressed, levodopa enhanced [3H]DA and [3H]NE uptake at low concentrations and inhibited the uptake at higher concentrations. The effects of levodopa on catecholamine transporters in the opposite direction suggest a different mechanism at the intra- and extracellular sites in a levodopa transport-dependent and independent manner.

Interferon-γ-producing B cells induce the formation of gastric lymphoid follicles after Helicobacter suis infection.

Helicobacter (H.) suis is capable of infecting various animals including humans, and H. suis infections can lead to gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Recently, we reported that interferon-γ (IFN-γ) was highly expressed in the stomachs of H. suis-infected mice, but the direct relationship between the upregulation of IFN-γ expression and the formation of gastric lymphoid follicles after H. suis infection remains unclear. Here, we demonstrated that the IFN-γ produced by B cells plays an important role in the formation of gastric lymphoid follicles after H. suis infection. In addition, IFN-γ-producing B cells evoked gastric lymphoid follicle formation independent of T-cell help, suggesting that they are crucial for the development of gastric MALT induced by Helicobacter infection.

Nitric oxide synergistically potentiates interleukin-1 beta-induced increase of cyclooxygenase-2 mRNA levels, resulting in the facilitation of substance P release from primary afferent neurons: involvement of cGMP-independent mechanisms.

We previously demonstrated that cultured rat dorsal root ganglion (DRG) cells respond to stimulation with interleukin-1 beta (IL-1 beta) by releasing substance P (SP), and this response is regulated via the cyclooxygenase (COX)-2 pathway. In this study, to ascertain the interaction between nitric oxide (NO) and prostaglandins in primary afferent neurons, we investigated the effect of NO on the IL-1 beta-induced release of SP in cultured DRG cells. An NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP), did not in itself evoke SP release. However, it potentiated the IL-1 beta-induced release of SP. Similarly, while SNAP did not elicit the expression of COX-2 mRNA, it potentiated the expression induced by IL-1 beta in cultured DRG cells, and this potentiation was significantly suppressed by the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO). Moreover, SNAP also potentiated the expression of COX-2 protein induced by IL-1 beta in cultured DRG cells. The stimulatory effect of SNAP on the IL-1 beta-induced release of SP was completely inhibited on co-incubation with a selective COX-2 inhibitor, NS-398. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ), a potent inhibitor of soluble guanylate cyclase, did not suppress, and a membrane-permeable cGMP analogue, 8-Br-cGMP, did not mimic the stimulatory effects of SNAP in DRG cells. These results suggest that in cultured DRG cells, NO potentiates the IL-1 beta-induced increase in COX-2 expression via a soluble guanylate cyclase-cGMP-independent pathway, resulting in facilitation of SP release. The interaction between NO and COX in primary afferent neurons might contribute to the change in nociceptive perception in inflammatory hyperalgesia.

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.

Evidence that prostaglandins activate calcium channels to enhance basal and stimulation-evoked catecholamine release from bovine adrenal chromaffin cells in culture.

The effects of prostaglandins (PGs) on catecholamine (CA) secretion and Ca2+ fluxes were studied in a primary culture of bovine chromaffin cells. PGD2, PGF2 alpha and PGE2 induced CA release from cultured bovine chromaffin cells in a concentration dependent manner (0.03-3 microM). PGD2, PGF2 alpha and PGE2 at 3 microM elicited maximum CA release of 0.043 +/- 0.001, 0.059 +/- 0.008, 0.062 +/- 0.002 micrograms/10(6) cells, respectively. Three micromolar of PGD2, PGF2 alpha and PGE2 enhanced CA release induced by acetylcholine (ACh) in a degree of 186 +/- 10, 206 +/- 6, 150 +/- 4% of control respectively. PGs also enhanced CA release induced by 20 mM K+, veratridine and A23187. In Ca2+-free medium, PGs failed to affect basal and caffeine (50 mM)-induced CA release. PGF2 alpha increased 45Ca uptake and showed additive effect with ACh on 45Ca uptake. Nicardipine (0.1-10 microM) suppressed CA release and 45Ca uptake induced by PGF2 alpha, while diltiazem and verapamil failed to affect these responses to PGF2 alpha. BAY K 8644 (1 microM) potentiated CA release and 45Ca uptake evoked by PGF2 alpha. These results suggest that PGs enhance basal and stimulation-evoked CA release from chromaffin cells possibly through facilitation of Ca2+ influx. The mechanisms of action of PGs in adrenal medulla are discussed.

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.

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.