Rolipram, a Specific Type IV Phosphodiesterase Inhibitor, Ameliorates Aspirin-Induced Gastric Mucosal Injury in Rats

Inhibition of type IV phosphodiesterase (PDE IV) activity reduces the production of various proinflammatory cytokine and suppresses neutrophil activation. Nonsteroidal anti-inflammatory drugs such as aspirin induce gastric mucosal lesions. In the pathogenesis of aspirin-induced gastric mucosal lesion, the contributions, of activated inflammatory cells and proinflammatory cytokine production are critical. The specific PDE IV inhibitor rolipram is known to be a potent inhibitor of inflammation by increasing intracellular cyclic AMP in leukocytes. The aim of the present study was to determine whether rolipram can ameliorate aspirin-induced gastric mucosal lesions in rats and whether the agent can inhibit the inrease in neutrophil accumulation and the production of proinflammatory cytokines. Gastric lesions were produced by administration of aspirin (200 mg/kg) and HCl (0.15 N; 8.0 ml/kg). Rolipram was injected 30 min before aspirin administration. The tissue myeloperoxidase concentration in gastric mucosa was measured as an indicat or of neutrophil infiltration. The gastric mucosal concentrations of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined by ELISA. The intragastric administration of aspirin induced multiple hemorrhagic erosions in rat gastric mucosa. Gastric mucosal lesions induced by aspirin were significantly inhibited by treatment with rolipram. The mucosal myeloperoxidase concentration was also suppressed by rolipram. Increases in the gastric content of TNF-α and IL-1β after aspirin administration were inhibited by pretreatment with rolipram. We demonstrated that the specific type IV PDE inhibitor, rolipram, could have a potent antiulcer effect, presumably mediated by its anti-inflammatory properties.     

LPS-Induced TNF-αRelease from and Apoptosis in Rat Cardiomyocytes: Obligatory Role for CD14 in Mediating the LPS Response

The bacterial endotoxin lipopolysaccharide (LPS) contributes to the cardiovascular collapse and death observed in patients with sepsis. Because LPS has such profound effects on cardiac performance, we speculate that direct effects of LPS could be demonstrated on cardiomyocytes in culture, and that these direct effects are mediated by the LPS receptor, CD14. Accordingly, in this study, we provide evidence for CD14-dependent cardiotoxic effects of LPS including the LPS-stimulated secretion of tumor necrosis factor alpha (TNF-α) from cardiomyocytes. TNF-αis an inflammatory cytokine which is known for its negative inotropic effects on cardiac performance, but has not until recently been shown to be produced by cardiac cells. In this study, LPS was found to stimulate strongly in a dose-dependent manner the secretion of TNF-αfrom cultured adult rat cardiomyocytes. Further, LPS-induced TNF-αsecretion was blocked by an inhibitor of TNF-αprocessing, metallomatrix protease inhibitor (TAPI). Molecular and immunological evidence demonstrated the presence of LPS receptors (CD14) on cardiomyocytes. Attenuated TNF-αsecretion following PI-PLC treatment confirmed the functional importance of CD14 for LPS-mediated myocardial effects. Importantly, LPS also triggered apoptosis in cultured cardiomyocytes as quantified by single-cell gel electrophoresis of nuclei exhibiting DNA fragmentation patterns characteristic of apoptosis (i.e. cardiac comets). Apoptotic cell death was blocked by pre-incubation with the soluble TNF-αreceptor fragment (TNFRII:Fc), suggesting that LPS-induced apoptosis was TNF-α-dependent and probably involved an autocrine function for the TNF-αwhose secretion was under LPS control. The results of this study suggest that the cardiodepressant effects of LPS are dependent on CD14 signaling and may not only be due to acute negative inotropic effects of TNF-αbut also may be complicated by TNF-α-induced apoptotic cell death which effectively reduces the number of working myocardial cells.     

Electrophysiological effects of amrinone on the automaticity and membrane current system of the rabbit sinoatrial node cells

Summary To elucidate the physiological role of phosphodiesterase (PDE) in cardiac pacemaker cells, we studied the electrophysiological effects of amrinone, an inhibitor of PDE type III, on the spontaneous action potential (AP) and membrane currents, using small preparations (0.2 × 0.2 × 0.1mm) of rabbit sinoatrial (SA) node cells. Amrinone (0.1–1.0mM) progressively increased the AP amplitude, maximal rate of depolarization, and spontaneous firing frequency, shortened the AP duration, and made the threshold potential more negative. In voltage-clamp experiments using double microelectrode techniques, 0.1mM amrinone increased the Ca²⁺ current (I _Ca) obtained on step depolarization from –40 to –10mV by 25.86% ± 4.6% (P < 0.05,n = 6), the delayed rectifier K⁺ current (I _K) tail obtained on repolarization from 10 to –60mV by 22.8% ± 4.7% (P < 0.05,n = 6), and the hyperpolarization-activated inward current (I _h) at –90mV by 19.5% ± 7.3% (P < 0.05,n = 6), respectively. Amrinone did not affect the slope factors of either the inactivation curve forI _Ca (f curve) or the activation curve for the delayed rectifierI _K (p curve). These results suggest that this PDE III inhibitor exerts a positive chronotropic action by enhancing the availability and the conductance of all the tested membrane currents in rabbit SA node cells.     

Human blood mononuclear cell in vitro cytokine response before and after two different strenuous exercise bouts in the presence of bloodroot and Echinacea extracts

The purpose of this multidisciplinary investigation was to characterize cytokine production by human blood mononuclear cells after 2 contrasting exercise bouts (a maximal graded oxygen consumption [VO₂max] test and 90 min of cycling at 85% of ventilatory threshold [VT]) when stimulated in vitro with extracts from bloodroot (Sanguinaria canadensis), coneflower (Echinacea tennesseensis), or solvent vehicle controls. Blood was sampled pre- and post-exercise. Production of TNF, IL-1β, and IL-10 were measured at 24, 48, and 72 h, respectively. In the VO₂max test there was a main effect of exercise such that exercise increased cytokine synthesis and a main effect of stimulant such that bloodroot extracts significantly increased cytokine production compared to other stimulants or controls. In the 90-min bout, there was a main effect of exercise for TNF and IL-1β (but not IL-10) such that exercise decreased cytokine synthesis and a main effect of stimulant such that bloodroot extracts significantly increased cytokine production compared to other stimulants or controls, with exercise × stimulant interactions for both IL-1β and IL-10. A similar though weaker effect was seen with Echinacea extracts; subsequent biochemical analyses suggested this was related to alkamide decay during 3 years undisturbed storage at ultralow (− 80 °C) temperature. In this study, the VO₂max test was associated with enhanced cytokine production whereas the 90-min cycling at 85% VT was associated with suppressed cytokine production. Bloodroot extracts were able to increase cytokine production in both contexts. Herbal extracts purported to offset exercise-associated effects on immune activity warrant continued investigation.     

Vesnarinone Inhibits Adenosine Uptake in Endothelial Cells, Smooth Muscle Cells and Myocytes, and Mediates Cytoprotection

Vesnarinone is a novel synthetic inotropic agent. Recently, it has been reported that vesnarinone inhibits adenosine uptake in the B-lymphocytoid cell line. Since extracellular adenosine is cardioprotective, we examined whether vesnarinone inhibits adenosine uptake in cells constituting the cardiovascular system. 1μCi of [³H]adenosine was added to cells of the myocyte cell line (C2C12), human coronary smooth muscle cell line (HCASMC), human and bovine coronary endothelial cell lines (HCAEC and BCAEC), bovine arterial endothelial cell line (BAEC), and human umbilical venous endothelial cell line (HUVEC). After 10 s–5 min, cells were separated from free [³H]adenosine, and the radioactivity was measured. When 0.1–100μ of vesnarinone was added to each cell line, the uptake of adenosine was inhibited dose-dependently {% inhibition of [³H]adenosine uptake at 10 and 30μ of vesnarinone: 14 and 33% (C2C12), 47 and 72% (HCASMC), 37 and 58% (HCAEC), 42 and 68% (BCAEC), 19 and 68% (BAEC), 29 and 59% (HUVEC)}. The cellular viability of HCAEC exposed to 60 min of hypoxia and 60 min of reoxygenation increased from 34±5 to 67±6% (Trypan blue exclusion test) and 23±5 to 78±6% (LDH release), which was completely blunted by 8-sulfophenyltheophylline, an adenosine receptor antagonist, and was partially blunted byα,β-methyleneadenosine 5′-diphosphate, an inhibitor of ecto-5′-nucleotidase. We also found that vesnarinone is cytoprotective against hypoxia and reoxygenation in C2C12 and HCASMC. We conclude that vesnarinone inhibits the uptake of adenosine in cardiovascular cells, which contributes to cytoprotection.     

Effect of Interleukin-18 on Viral Myocarditis: Enhancement of Interferon- γ and Natural Killer Cell Activity

Encephalomyocarditis virus causes viral myocarditis with myocyte necrosis and inflammatory cell infiltration in mice. Because previous studies have shown that some cytokines prevent the sequelae of myocarditis, we assessed the effect of a newly identified cytokine, interleukin-18 (IL-18), in preventing the sequelae of myocarditis. Murine IL-18 (10μ g/day/mouse) was given peritoneally for 10 days in C3H mice infected with EMC virus. Mice were divided into group IL-18 (infected-treated), saline group (infected-untreated), group IL-18-2 (treatment started on day 2), group IL-18-5 (treatment started on day 5). Although the 14-day survival rate in saline group was 20%, that in the group IL-18 increased to 80% (P<0.05). Either mice in group IL-18-2 or in group IL-18-5 did not survive longer than saline group. The viral titer of the heart on day 3 was lower in group IL-18 compared to the saline group (1.00±0.20 log₁₀tissue culture infected dose (TCID)₅₀/mg wet weight v 1.42±0.12 log₁₀TCID₅₀/mg,n =3 of each). Mice in group IL-18 had less myocardial necrosis and cellular infiltration than the saline group. The myocardial expression of interferon- γ (IFN- γ) mRNA in group IL-18 was significantly (P<0.05) greater than the saline group on days 1 and 3 after viral inoculation. Circulating IFN- γ was significantly elevated on days 1, 5, and 7, but significantly reduced on day 3. The natural killer cell activities in the spleen on days 1, 3, and 5 were significantly (P<0.05) greater in group IL-18 than in the saline group (41±9%v 10±6% on day 3, 4 of each). We conclude that IL-18 reduces the severity of EMC viral myocarditis by inducing cardiac expression of IFN- γ mRNA and increasing splenic natural killer cell activity.     

The Nitric Oxide Donor SIN-1 Protects Endothelial Cells from Tumor Necrosis Factor-α-Mediated Cytotoxicity: Possible Role For Cyclic GMP and Heme Oxygenase

In cultured endothelial cells, incubation with TNF-α(50 ng/ml) for 72 h markedly reduced viability of endothelial cells. A 6-h pre-incubation with the nitric oxide (NO) donor linsidomine (SIN-1, 10–150μ ) protected endothelial cells in a concentration-dependent manner and increased viability by up to 59% of control. The unmetabolized parent compound molsidomine and the NO-free metabolite of SIN-1 3-morpholinoiminoacetonitrile (SIN-1C) were without cytoprotective effect. Cytoprotection by SIN-1 was completely abolished by the NO scavenger 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl-3-oxide (PTIO, 30μ ). A cytoprotective effect comparable to SIN-1 was observed when preincubating the cells with dibutyryl cyclic GMP (10–100μ ). Moreover, no protection by SIN-1 occurred in the presence of cycloheximide (1μ ) or 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ, 0.1μ ), a selective inhibitor of soluble guanylyl cyclase. Tin protoporphyrin-IX (SnPP, 25μ ), an inhibitor of heme oxygenase, was found to attenuate SIN-1-induced cytoprotection. Our results demonstrate that SIN-1 produces a long-term endothelial protection against cellular injury by TNF-α, presumably via a cyclic GMP-dependent pathway leading to up-regulation of protective proteins such as heme oxygenase.     

Contribution of cAMP-phosphodiesterase inhibition and sensitization of the contractile proteins for calcium to the inotropic effect of pimobendan in the failing human myocardium.

Previous studies have shown reduced effects of cAMP-dependent positive inotropic agents in the failing human myocardium; thus other cAMP-independent mechanisms of action may be useful to increase force of contraction in this condition. The purpose of this investigation was to determine whether a positive inotropic effect of the cAMP-phosphodiesterase (PDE) inhibitor pimobendan is observed in the failing human myocardium and to study whether other factors, such as an increase in the Ca2+ sensitivity of myofilaments, play a functional role in the increase in force of contraction. Pimobendan produced a positive inotropic effect in isolated preparations from nonfailing donor hearts; however, in moderately (New York Heart Association class II-III, NYHA II-III) and severely (NYHA IV) failing myocardium, this effect was reduced. In addition, in NYHA IV specimens pimobendan inhibited the crude cAMP-PDE (crude PDE) and the isoenzymes I-III (PDE I-III) in a concentration-dependent way. As judged from the IC50 values found in this tissue for the inhibition of PDE III and of crude PDE, the potency of the compound was 18.1 times greater on PDE III. Consistent with a cAMP-PDE-dependent mechanism of action, the positive inotropic effect was potentiated by isoproterenol and inhibited by adenosine in failing myocardium. In failing myocardium, pimobendan also increased the sensitivity of skinned cardiac fibers to Ca2+ and shifted the Ca(2+)-tension relation to the left. This sensitizing effect began at 0.01 mumol/l in NYHA II-III and NYHA IV and rose to about 200% at 300 mumol/l in both groups. In contrast, the demethylated metabolite UD-CG 212 Cl failed to produce positive inotropic effects in failing myocardium alone, but in the presence of isoproterenol, it exerted an increase in force of contraction. The potency of UD-CG 212 Cl for PDE III inhibition in NYHA IV was greater than that of pimobendan. The metabolite pronouncedly decreased the sensitivity of skinned cardiac fibers to Ca2+ at 30-300 mumol/l in NYHA II-III and NYHA IV. It is concluded that in the failing human heart pimobendan inhibited PDE III and sensitized contractile proteins for Ca2+. Both effects appear to be involved in the positive inotropic effect of the compound, because its metabolite, UD-CG 212 Cl, had no effect on force of contraction and on the Ca2+ sensitivity of skinned cardiac fibers but inhibited PDE III even more potently than pimobendan.(ABSTRACT TRUNCATED AT 400 WORDS)     

Temperature and Serum Proinflammatory Cytokine Changes in Patients with NSCLC after BAL

We examined the effects of bronchoalveolar lavage (BAL) and BAL fluid characteristics on the systemic proinflammatory cytokine expression and their relation to clinical and laboratory findings. Thirty patients suspected to have lung cancer were subjected to fiber-optic bronchoscopy (FOB) and BAL. Clinical and laboratory findings were determined at baseline, 4 h, and 24 h, including lung auscultation, temperature, chest X-ray, WBC, neutrophils, and serum IL-1, IL-6, and TNF-. BAL fluid characteristics were determined including cytokine levels. Fifteen volunteers served as controls to determine serum variation of the same cytokines. Significant temperature elevation was defined as 1°C increase compared to baseline. BAL was associated with temperature and serum TNF- and IL-6 but not IL-1 increase at 4 h. Four patients (13.3%) developed temperature over 38°C. In controls there were no significant changes between baseline and 24 h measurements for the same cytokines. Eleven patients (36.6%) developed a significant temperature elevation 4 h after BAL. These patients had a statistically significant (p < 0.05) increase in serum IL-6 at 4 h and in TNF- at both 4 and 24 h after BAL compared with the nonsignificant temperature increase group. BAL characteristics were not different between the two groups. On the other hand, BAL fluid IL-6 and TNF- levels were significantly higher (p < 0.05) in the nonfever group. Significant temperature increase was observed in 36.6% of the patients undergoing BAL and associated with significant serum TNF- and IL-6 increase at 4 h. Lung cytokines levels, alveolar macrophages, and BAL fluid characteristics are not related to temperature and serum proinflammatory cytokine increase. The hypothesis of alveolar macrophages derive from cytokine production and shift to the systemic circulation cannot be supported by our data. Abbreviations: NSCLC = non-small-cell lung carcinoma, BAL = bronchoalveolar lavage, FOB = fiber-optic bronchoscopy, IL-6 = interleukin 6, IL-1 = interleukin 1-beta, TNF- = tumor necrosis factor alpha, WBC = white blood cells, G-CSF = granulocyte colony stimulating factor, IM = intramuscular, ECG = electrocardiogram.     

Sex differences in postprandial plasma tumor necrosis factor–α, interleukin-6, and C-reactive protein concentrations

Abdominal obesity and insulin resistance are characterized by low-level chronic inflammation most likely implicated in the increased cardiovascular disease risk associated with these conditions. However, not much is known of the acute regulation of circulating inflammatory markers in response to food intake. The aim of this study is to examine changes in inflammatory marker concentrations after the consumption of a high-fat meal in men and women. We measured tumor necrosis factor–α (TNF-α), interleukin-6 (IL-6), and C-reactive protein concentrations in plasma samples collected at 0, 4, and 8 hours after consumption of the meal in 39 men and 41 women. Associations between these variations and physical as well as metabolic variables were then examined. We noted significant increases in plasma IL-6 concentrations at 4 and 8 hours after the meal in men (+34% and +107%, respectively; P < .005 vs 0 hour) and women (+78% and +153%, respectively; P < .0001 vs 0 hour). Postprandial plasma TNF-α concentrations significantly dropped at 4 hours after the high-fat meal in men (−9.5%, P < .0005 vs 0 hour) and women (−5.5%, P < .05 vs 0 hour). Plasma CRP concentrations were not affected by food intake in either men or women. We also found that postprandial plasma concentrations of IL-6 were lower in subjects with a normal glucose tolerance (n = 69) compared with individuals with an impaired glucose tolerance (n = 11). Results of the present study show that consumption of a high-fat meal is associated with a transient reduction in circulating concentrations of TNF-α in both men and women as well as an elevation of plasma IL-6 concentrations that was found to be greater in women than in men.     

Interleukin-1β up-regulates tumor necrosis factor receptors in the mouse airways

Cytokines like interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα), released during the inflammatory process, play important roles in the development of airway hyperresponsiveness. The effects of these cytokines are mediated by cell surface receptors, specific for each cytokine. The expression of cytokine receptors is a dynamic process, where receptors can be up- or down-regulated in response to changes in the environment. One such environmental factor is the presence of cytokines per se. The present study was designed to evaluate the effects of IL-1β on the expression of its corresponding receptor IL-1 RI, as well as on the closely related TNFα receptors TNF RI and TNF RII in airways using a mouse organ culture assay and intranasal inoculation model. Immunohistochemical staining was used to quantify expressional differences between fresh and cultured tracheal segments. In the fresh, uncultured, segments, IL-1 RI and TNF RI were seen in the epithelial layer and TNF RI in the smooth muscle layer. After 4 days of culture, the expression of TNF RI decreased in the epithelial layer, whereas the corresponding expression of IL-1 RI and TNF RI in the smooth muscle remained unchanged. When culture was performed in the presence of IL-1β, the expression of IL-1 RI and TNF RI in the epithelial cells and TNF RI in the smooth muscle cells increased. TNF RII was not detected in either fresh or cultured trachea, but after treatment with IL-1β an expression was found in both the epithelial layer and in the smooth muscle cells. The IL-1β-induced increased expression, on TNF RI and TNF RII in the smooth muscle ex vivo and in the lung parenchyma after intranasal challenge in vivo, was verified at the mRNA level using real-time RT PCR. To summarize, presence of IL-1β increases the expression of IL-1 R1 and TNF RI and induces expression of TNF RII in the airway wall. It is not inconceivable that these alterations of the IL-1 and TNF receptors may have important functional implications for the development of hyperresponsiveness in inflammatory airway diseases like asthma.     

Plasma Interleukin-10: A Likely Predictive Marker for Hepatitis B Virus-Related Acute-on-Chronic Liver Failure

Background:

The pathogenesis of HBV-related acute-on-chronic liver failure (HBV-ACLF) is mainly based on a heightened immune-inflammatory reaction; however, the intimate underlying mechanism remains unclear.

Objectives:

The aim of the study was to explore potential key immune molecular targets that could serve as early predictive markers for HBV-ACLF.

Patients and Methods:

Twenty-seven patients with acute exacerbation of chronic hepatitis B (CHB) (defined by: alanine transaminase ≥ 20 ULN, total bilirubin ≥ 5 ULN, 40% < prothrombin time activity ≤ 60%) and without cirrhosis were divided into 18 cases which did not progress to HBV-ACLF (defined by: prothrombin time activity < 40% and development within four weeks of hepatic encephalopathy and/or ascites) and nine cases that developed HBV-ACLF. Nine healthy people defined the normal control group (NC). Interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, TNF-α and IFN-γ protein levels were assayed by Cytometric Bead Array (CBA) in blood plasma. The ELISA method was applied to confirm IL-10 detection using the CBA method.

Results:

IL-4, IL-12p70 and IFN-γ were undetectable; IL-1β, IL-6, IL-8, IL-10 and TNF-α levels were significantly higher than in NC. Moreover, cytokines reached the highest levels in acute exacerbation of CHB, with the exception of IL-2 and IL-8. When comparing the HBV-ACLF patients prior to and at the time of ACLF diagnosis, IL-10 was the only cytokine that exhibited a significant decrease (P = 0.008). IL-10 concentrations were positively correlated to ALT levels (r = 0.711, P < 0.001).

Conclusions:

The assessment of plasma IL-10 levels in chronic hepatitis B acute exacerbation may provide an early predictive marker for progression to HBV-ACLF.     

The Value of Plasma Cytokine Measurement for the Detection of Strangulation in Patients With Bowel Obstruction: A Prospective, Pilot Study

PURPOSE The aim of this prospective blinded study was to examine whether measurement of plasma cytokines is a predictor of strangulation in patients with bowel obstruction.METHODS Seventy-seven consecutive patients diagnosed with bowel obstruction were included. Blood samples were obtained at enrollment in all patients and at surgery (immediately before operation) if patients required surgery.RESULTS Forty-three patients were managed conservatively (group 1) and 34 patients required surgery, of whom 20 had no bowel strangulation (group 2) and 14 had bowel strangulation (group 3). The mean plasma interleukin (IL)-6 levels at enrollment were significantly higher in group 3 (107.8 pg/ml) than in groups 1 (11.3 pg/ml, P < 0.0001 vs. group 3) and 2 (23.6 pg/ml, P < 0.0001 vs. group 3). The sensitivity and specificity of plasma IL-6 level (≥40 pg/ml) in predicting strangulation were 86 percent (95 percent confidence interval, 60–97 percent) and 86 percent (95 percent confidence interval, 80–88 percent), respectively. The plasma IL-6 levels at surgery significantly increased compared to those at enrollment (from 107.8 pg/ml to 205.8 pg/ml, P = 0.0003) in group 3, however, they did not increase significantly in group 2. Among other clinical and laboratory parameters, plasma lactic acid levels (≥15 mg/dl) at enrollment were significantly associated with strangulation. In the multivariate analysis, both plasma IL-6 (相似文献   

Relationship between IL-1β gene polymorphism and gastric mucosal IL-1β levels in patients with Helicobacter pylori infection

Background Interkeukin-1 (IL-1) gene cluster polymorphisms that are thought to enhance the production of IL-1β are associated with an increased risk of gastric cancer. To determine the role of host genetic factors in Helicobacter pylori infection, we examined the relationship between gastric mucosal IL-1β levels and IL-1B polymorphisms in patients with H. pylori infection.Methods Biopsy tissues obtained from 99 patients were homogenized and gastric mucosal IL-1β levels were measured by enzyme-linked immunosorbent assay (ELISA). Single-base polymorphisms at positions −511 and −31 in IL-1B were analyzed.Results The IL-1β level in the antrum was significantly higher in genotype IL-1B-511C/C than in H. pylori-negative patients (P < 0.05). The IL-1B polymorphism did not influence the degree of gastric neutrophil and mononuclear cell infiltration, or gastric atrophy. IL-1β levels in the corpus, but not those in the antrum, correlated to the severity of gastric atrophy.Conclusions These findings indicate that IL-1B polymorphisms enhance IL-1β production in the antrum; however, other factors might regulate the production of IL-1β in the corpus of the stomach, regardless of IL-1B polymorphisms, and high IL-1β production may be associated with the grade of gastric atrophy in the corpus mucosa in patients with H. pylori infection.     

Effects of a phosphodiesterase III inhibitor on circulating blood volume after cardiopulmonary bypass

Using a new method based on pulse dye densitometry, circulating blood volume (BV) was measured without direct sampling in patients undergoing open-heart surgery, and the effects of phosphodiesterase (PDE) III inhibitor administration during cardiopulmonary bypass (CPB) were evaluated. Sixteen patients scheduled for elective coronary artery bypass grafting were randomly assigned to the PDE III inhibitor group or control group. BV was determined before CPB, and immediately, and 4 and 12 h after operation. After declamping of the aorta, the PDE III inhibitor amrinone (1 mg/kg) was infused as a single bolus into the venous reservoir in the PDE III inhibitor group. BV decreased significantly soon after the operation in the control group. It did not decrease in the PDE III inhibitor group (48.6 ± 44 and 60.6 ± 8.0 ml/kg for the control and PDE III inhibitor groups, respectively). Four hours after surgery and beyond no significant changes in BV were observed in either group. The body fluid balance was negative in both groups. In conclusion, a single administration of PDE III inhibitor during CPB was found to sustain BV soon after operation and, therefore, is useful for postoperative management of open-heart surgery. Received: May 1, 2000 / Accepted: September 30, 2000     

Low-dose interferon-alpha accelerates atherosclerosis in an LDL receptor-deficient mouse model

Background: Solid evidence suggests that atheroscleosis is associated with immune reactions. Most of the activated T cells in the plaque are T helper 1 subtype (Th1), which secrete interferon-γ (IFN-γ), now generally accepted as a proatherogenic cytokine. Interferon-α (IFN-α) has been found to inhibit the secretion of IL-12 and IFN-γ and to increase IL-10 production. It may, therefore, be atheroprotective. The aim of the present study was to clarify the effect of IFN-α on atherogenesis in a transgenic mouse model of atherosclerosis. Methods: 8-week-old low-density lipoprotein (LDL) receptor-deficient mice were allocated randomly into treatment and control groups (n=13 each). The treatment group received 1000 units of IFN-α i.p. every other day for 5 weeks and the control mice received 0.9% NaCl. The mice were fed a Western diet. Results: The IFN-α-treated and the control mice showed a similar weight gain (mean 3.9±1.0 g vs. 3.4±1.8 g, respectively). Treatment with IFN-α significantly increased the plasma cholesterol levels in both treated and untreated mice (mean 31.03±5.53 mmol/l vs. 24.91±6.03 mmol/l, respectively; p<0.022) as well as the plasma triglyceride levels (mean 4.79±1.57 mmol/l vs. 3.10±1.85 mmol/l, respectively; p<0.033). The IFN-α treated mice had a significantly increased atherosclerotic plaque area (mean 61,590±22,368 μm² vs. 37,272±15,469 μm², respectively; p<0.008). Conclusion: The putative atheroprotective effect of IFN-α by the decrease in IL-10 and IFN-γ is abolished by hyperlipidemia. Therefore, the net effect of IFN-α in this murine model is the exacerbation of atherosclerosis.     

Subclasses of cyclic AMP-specific phosphodiesterase in left ventricular muscle and their involvement in regulating myocardial contractility

Ventricular muscle contains a low Km, cyclic AMP-specific form of phosphodiesterase (PDE III), which is believed to represent the site of action for several of new cardiotonic agents including imazodan (CI-914), amrinone, cilostamide, and enoximone. However, species differences in the inotropic response to these agents have raised questions about the relationship between PDE III inhibition and cardiotonic activity. The present study demonstrates that these differences can be accounted for by the presence of two subclasses of PDE III in ventricular muscle and variations in the intracellular localization of these two enzymes. For these experiments, PDE III was initially isolated from canine, guinea pig, and rat left ventricular muscle. The results demonstrate that canine left ventricular muscle contains two functional subclasses of PDE III: an imazodan-sensitive form, which is membrane bound, and an imazodan-insensitive form, which is soluble. Although only weakly inhibited by imazodan, this latter enzyme is potently inhibited by the selective PDE III inhibitors, Ro 20-1724 and rolipram. Guinea pig ventricular muscle also contains the imazodan-sensitive subclass of PDE III. Unlike canine left ventricle, however, thi enzyme is soluble in the guinea pig. No membrane-bound subclass of PDE III was observed in the guinea pig. Rat left ventricle possesses only the soluble form of PDE III, which apparently represents a mixture of the imazodan-sensitive and imazodan-insensitive subclasses of PDE III. Measurement of in vivo contractility in these three species showed that imazodan exerts a potent positive inotropic effect only in the dog, in which the imazodan-sensitive subclass of PDE III is membrane bound.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tumour necrosis factor-α enhances intraepithelial lymphocyte proliferation and migration

Background—Tumour necrosis factor α (TNF-α)is a proinflammatory cytokine found in abundance in diseased intestine.
Aims—The T cell production of TNF-α and theimpact of this cytokine on intestinal T cell proliferation, migration,and cytotoxicity were studied.
Methods—Intestinal lymphocytes from normaljejunum were used. TNF-α production in culture supernates wasmeasured by enzyme linked immunosorbent assay (ELISA). Lymphocyteproliferation was measured using ³H thymidine uptake;migration, using transwell chambers; and cytotoxicity of HT-29 coloncancer cells, using the chromium-51 release assay.
Results—TNF-α was produced mainly by the CD8+ Tcells in the intraepithelial lymphocytes (IEL) and the CD4+ T cells inthe lamina propria lymphocytes in response to CD2 stimulation: 478(94)and 782 (136) pg/ml, respectively. TNF-α (1 ng/ml or greater) augmented proliferation of IEL in response to interleukin 2 (IL-2), IL-7, or antibody to CD3 due to increased activation that did notinvolve IL-2 production or receptor generation. Conversely, antibody toTNF-α reduced IEL proliferation in response to IL-2 or IL-7. TNF-αalso induced calcium mobilisation and chemokinesis (by 2.8 (0.5) foldover spontaneous migration). TNF-α had no effect on lymphokineactivated killer cell activity.
Conclusions—TNF-α increases the proliferationand migration of IEL, which may expand their number in the epithelium.