The effect of a therapeutic doxycycline concentration on polymorphonuclear leukocyte migration in vitro

Tetracyclines, and especially doxycycline, have been reported to inhibit polymorphonuclear leukocyte (PMN) migration. The effect of a therapeutic doxycycline concentration (4.33 micrograms/ml) on PMN migration in vitro was tested with the leading-front technique. No significant effect could be demonstrated on PMN chemokinesis and chemotaxis. It is thus concluded that the effect of therapeutic doxycycline concentrations on PMN migration is negligible. This conclusion has a bearing upon the choice of antimicrobial therapy.     

Comparison between the effects of aging on antagonist and agonist interactions with beta-adrenergic receptors on human mononuclear and polymorphonuclear leukocyte membranes

Age-related differences in the binding properties of beta-adrenergic receptors on lymphocyte membranes isolated from healthy individuals have been reported. The purpose of the present studies was to determine whether or not beta receptors on polymorphonuclear leukocyte (PMN) membranes showed similar age-related changes. Plasma Percoll gradients were used to isolate PMN and mononuclear leukocyte (MN) cells from blood drawn in the supine position from young (25-34 years) and elderly (60-76 years) healthy volunteers. Both blood pressures and plasma norepinephrine levels were significantly elevated in the elderly subjects. Saturation analysis with [125I]-(-) iodopindolol (IPIN) showed a 2.5-fold higher density of beta 2 receptors on the MN, but not PMN, membranes from the elderly. Neither the affinities of the receptor for IPIN or the agonist isoproterenol, nor the GTP-induced shift in agonist affinity, differed with subject age in either cell type. These results suggest that subpopulations of MN cells on which beta-adrenergic receptors are localized may increase in the elderly and that it is important to measure receptor properties on a more homogeneous leukocyte population such as PMN cells or subpopulations of MN cells as a function of aging.     

The effect of vanadyl treatment on vascular responsiveness of streptozotocin-diabetic rats

Summary Vanadyl sulphate has been demonstrated to possess insulin-like effects in streptozotocin (STZ) diabetic rats, including the normalization of hyperglycaemia and the prevention of diabetes-induced cardiac dysfunction. However, the effectiveness of vanadyl sulphate on diabetes-related vascular aberrations has not been questioned. Hence, in the present work, we have specifically addressed the question of whether chronic oral vanadyl sulphate treatment has any beneficial effect on diabetes-induced changes in vascular reactivity. Male albino rats were injected with a single intravenous dose of STZ (55 mg/kg). Vanadyl sulphate was administered in the drinking water at a concentration of 1 mg/ml from 7 days after the STZ injection and treatment was maintained for 10 weeks. Vanadyl intake was accompanied by decreased blood glucose and serum insulin levels. The effects of diabetes on vascular smooth muscle function were assessed by the responsiveness of aortae to noradrenaline and KCl. Contractile responses of the diabetic aortae were found to be significantly increased as compared with controls. However, there were no significant differences in pD₂ values of the agonists in either of the groups. Treatment of diabetic rats with vanadyl sulphate completely prevented the increases in responsiveness of aortae to noradrenaline and KCl. The effect of diabetes on the fast and slow components of noradrenaline-induced contraction was also examined. Both components of the response to noradrenaline were significantly increased in diabetic aortae. These changes were also prevented by vanadyl sulphate treatment. The data demonstrate that 10-week vanadyl sulphate treatment results in improved vascular reactivity of diabetic rats.Abbrevations STZ streptozotocin - VST vanadyl sulphate trihydrate     

中性粒细胞分泌功能与支气管哮喘

哮喘是由多种炎症细胞和炎症组分参与的气道慢性炎症。近年来发现中性粒细胞(PMN)在哮喘的发病机制中也起重要作用,尤其表现在重度哮喘和致命性哮喘中。激活的PMN能分泌多种酶、炎症介质和细胞因子等参与哮喘的发病过程。在此,对PMN分泌功能在哮喘中的作用作一综述。     

New assessment of airway responsiveness. Effect of pretreatment with procaterol on allergen-induced bronchoconstriction

We examined airway responsiveness to allergen inhalation using a novel technique by which dynamic compliance (Cdyn) and pulmonary resistance (Rl) are simultaneously calculated by Fourier-series analysis of flow and transpulmonary pressure during tidal breathing. C0 and C0.5 (Cdyn at the frequency of zero and 0.5 Hz, respectively) were computed using the regression line of Cdyn versus frequency measured at the fundamental and first three harmonics in each breathing cycle. First, the validity of this system was tested by comparing Rl, C0 and C0.5 during five consecutive breaths with those obtained by the conventional method. A good correlation was seen in Rl, C0 and C0.5 between the two methods. Second, we studied airway response to allergen inhalation before and after oral administration of a long-acting beta 2-stimulant (procaterol, 50 micrograms or 100 micrograms) or placebo in a double-blind crossover trial in six atopic asthmatic subjects. In control allergen inhalation tests by administration of placebo, Rl increased progressively, and C0.5, expressed as percentage of control compliance at zero frequency (C0.5/COcont), decreased progressively. After 100 micrograms procaterol, Rl response to allergen was almost completely inhibited. However, a decrease in C0.5/C0cont was still observed. These findings suggest that pretreatment of asthmatic patients with procaterol can release allergen-induced bronchoconstriction of the central airways, but cannot release that of the peripheral airways.     

Platelet-dependent modulation of polymorphonuclear leukocyte chemiluminescence

Human blood platelets decreased luminol-enhanced chemiluminescence of human polymorphonuclear leukocytes (PMNL) stimulated with FMLP or Ca2+-ionophore A23187 by 56 or 47%, respectively. Horseradish peroxidase potentiated the decreasing effect of platelets on A23187-stimulated PMNL (92% inhibition) or reversed inhibition of FMLP-induced chemiluminescence to 94% potentiation, indicating dependence of platelet activity on availability of extracellular peroxidase. Moreover, platelet activity may depend also on the extent of platelet activation, as non-activated platelets (in the presence of FMLP) were found to potentiate PMNL-generated chemiluminescence, while platelets activated with A23187 displayed the opposite effect. Interference of platelets with formation and liberation of superoxide anion was indicated by platelet-modified isoluminol chemiluminescence. Superoxide dismutase with catalase and sodium azide were used, respectively, to differentiate the intracellular and the extracellular part of the chemiluminescence signal. Platelets were found to be capable of modifying both components of chemiluminescence, i.e., oxygen metabolites produced on the plasma membrane as well as on membranes of intracellular granules.     

Platelet-dependent modulation of polymorphonuclear leukocyte chemiluminescence

Human blood platelets decreased luminol-enhanced chemiluminescence of human polymorphonuclear leukocytes (PMNL) stimulated with FMLP or Ca2+-ionophore A23187 by 56 or 47%, respectively. Horseradish peroxidase potentiated the decreasing effect of platelets on A23187-stimulated PMNL (92% inhibition) or reversed inhibition of FMLP-induced chemiluminescence to 94% potentiation, indicating dependence of platelet activity on availability of extracellular peroxidase. Moreover, platelet activity may depend also on the extent of platelet activation, as non-activated platelets (in the presence of FMLP) were found to potentiate PMNL-generated chemiluminescence, while platelets activated with A23187 displayed the opposite effect. Interference of platelets with formation and liberation of superoxide anion was indicated by platelet-modified isoluminol chemiluminescence. Superoxide dismutase with catalase and sodium azide were used, respectively, to differentiate the intracellular and the extracellular part of the chemiluminescence signal. Platelets were found to be capable of modifying both components of chemiluminescence, i.e., oxygen metabolites produced on the plasma membrane as well as on membranes of intracellular granules.     

Intraabdominal sepsis: enhanced autooxidative effect on polymorphonuclear leukocyte cell surface receptor expression.

We investigated the effects of untreated intraabdominal sepsis on the interrelationship between PMN oxidative metabolism and cell surface receptor expression. Female swine underwent either sham laparotomy (n = 7) or cecal ligation and incision (n = 9) with assays conducted on postoperative days (POD) 0, 1, 4, and 8. Superoxide anion production, intracellular H2O2 production, and the cell surface expression of Fc gamma RII, III, CR1, and CR3 were measured. In addition, phagocytosis of serum-opsonized zymosan was used as a multivalent ligand for CR3 and subsequently Fc gamma RII, III, and CR1 expression were assayed to determine if intraabdominal sepsis induces a linkage between complement and Fc gamma receptor expression. Superoxide anion production increased between POD 0 and 4 and fell between POD 4 and 8 in animals with untreated intraabdominal sepsis. Intracellular H2O2 production rose between POD 0 and 1 and then fell progressively in animals with untreated intraabdominal sepsis. Simulation of the oxidative burst using glucose/glucose oxidase reduced Fc gamma RII and III expression in both sets of animals with a greater reduction seen by POD 4 in animals with intraabdominal sepsis. CR1/CR3 expression was increased with glucose/glucose oxidase by POD 4 in the presence of intraabdominal sepsis. Xanthine/xanthine oxidase did not alter cell surface receptor expression. Phagocytosis of serum-opsonized zymosan decreased subsequent Fc gamma RII expression in animals with intraabdominal sepsis by POD 4.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship between nonspecific bronchial responsiveness to methacholine and peripheral mononuclear leukocyte beta-adrenergic receptor function in young drug-naive subjects.

Asthma is associated with dysfunction of the beta-adrenergic receptor adenylyl cyclase signal transduction pathway. It has been argued that this results from receptor down-regulation by beta-agonist therapy. This study examined the relationship between nonspecific bronchial responsiveness (NSBR) to methacholine (Newcastle dosimeter method) and beta-adrenergic receptor density (Bmax) and affinity (%KH) in membranes from peripheral blood mononuclear leukocytes (MNL) in 12 male (27.3 +/- 1.7 yr old) and 14 female (31.4 +/- 1.7 yr old) drug-naive subjects with and without symptoms of mild intermittent wheezing. None had ever smoked or received any antiasthma medication. "Hyperresponsive" subjects were defined as those (n = 11) whose simplified slope of FEF50 (calculated as the percent fall in FEF50 divided by the dose of methacholine) was more than one SD above the mean for asymptomatic subjects. The log of the slope was reproducible (repeatability coefficient = 0.43) on two nonconsecutive days. Multiple regression analysis (overall R2 = 0.57) revealed negative relationships between the log of the slope and both Bmax (p = 0.016) and %KH (p = 0.011). Analysis of variance confirmed a lower mean (+/- SEM) value of %KH in "hyperresponsives" (45.7 +/- 5.5%) than in "normoresponsives" (60.4 +/- 4.1%, p = 0.04) with a similar trend for Bmax (hyperresponsives = 33.5 +/- 4.1 fmol/mg, normoresponsives = 45.9 +/- 7.1 fmol/mg, p = 0.18). These relationships between bronchial responsiveness, Bmax, and %KH cannot be explained by drug therapy, and they provide further evidence that there is an intrinsic impairment in the function of beta-adrenergic receptors on peripheral MNLs from subjects with high levels of nonspecific bronchial responsiveness.     

The influence of hyperthyroidism and hypothyroidism on alpha- and beta-adrenergic receptor systems and adrenergic responsiveness

A detailed review has been conducted of studies addressing dressing the subject of the influence of thyroid hormone on alpha- and beta-adrenergic receptors and adrenergic responsiveness in a wide range of experimental animals and tissues. The studies summarized in the present article have been restricted to those in which explicit measurements of receptor number were made by the use of appropriate radioligands. Particular emphasis is given to an examination of the relationship between thyroid hormone-induced changes in alpha- and beta-adrenergic receptor number and accompanying changes in adenylate cyclase activity and more distal adrenergic responses. Although in many instances thyroid hormone-induced changes in receptor number are reflected in coordinate changes in adrenergic sensitivity, this is shown to be by no means uniformly the case. In contrasting instances, modifications at other more distal sites in the sequence of events mediating catecholamine hormone action are responsible for biochemical and physiological changes in catecholamine responsiveness induced by thyroid hormone.     

Neuroendocrine thymus and beta-adrenergic responsiveness in aging mice

It has previously been shown that thymus exerts a regulatory influence on the beta-adrenergic system, controlling, in particular, DNA synthesis in submandibular glands following injection with isoproterenol (IPR). A decreased peak of response found in old mice can be corrected by grafting a neonatal thymus into old animals. In order to clear whether its restoring action needs mutual interrelationships with other control systems or, alternatively, whether even some thymic factor can be effective, the IPR response mentioned above was also assayed in old animals treated with a thymic extract (TME). Among the numerous thymic factors, this extract was chosen due to the effect that it was prepared on the basis of non-immunological tests and had already been shown to be effective in correcting some alterations observed in old rats. Results show that TME is capable of partially restoring the impaired response found in old mice. The location of the peak of thymidine incorporation, however, is shifted towards the right with respect the peak time observed in young, old and thymus-grafted old mice. Without additional studies, it cannot be decided whether the shift and the only partial recovery is due to the particular dose and duration of the treatment or represents a weaker action of the extract with respect to that of thymic graft.     

支气管舒张试验对AECOPD小气道功能影响

目的 探讨支气管舒张试验对慢性阻塞性肺疾病急性加重期(AECOPD)小气道功能影响.方法 分析我院2008年1月至2011年4月38例AECOPD患者,行支气管舒张试验,FEV1、FEF 50％、FEF 75％、MMEF 75/25％行配对t检验.结果 支气管舒张试验在AECOPD及支气管舒张试验阳性组小气道功能均存在显著差异;在支气管舒张试验阴性组,FEV1、FEF 50％存在显著差异,但FEF 75％、MMEF 75/25％无差异.结论 支气管舒张试验可改善AECOPD患者小气道功能,但在支气管舒张试验阴性组小气道功能指标FEF 75％、MMEF 75/25％无改善.     

The role of phospholipase in reduced beta-adrenergic responsiveness in experimental asthma

This investigation was designed to elucidate the role of phospholipase (PLase) in relation to reduced beta-adrenergic responsiveness in guinea pigs subjected to experimental asthma. In the in vivo experiment, guinea pigs that had developed asthma-like symptoms after exposure to an aerosol of 2% ovalbumin for 7 to 8 min for 10 successive days were used as the experimental asthma group. The control group was exposed to saline. The endogenous PLase activity was determined by high performance liquid chromatography using ditridecanoyl phosphatidylcholine as a substrate. PLase activity of lung membranes in the experimental asthma group was significantly elevated by 50% compared with that in the control group. Phospholipid content of lung membranes in the experimental asthma group was decreased by 11% compared with that in the control group. The experimental asthma group showed a 37% decrease in the number of beta-adrenoceptors in lung membranes and a 54% decrease in isoproterenol-stimulated adenylate cyclase activity in lung membranes compared with the control group. Although forskolin-stimulated adenylate cyclase activity was also reduced by 24%, decreases in forskolin-stimulated activity were less than decreases in isoproterenol-stimulated activity. In the in vitro experiment phospholipids in lung membranes were degraded by pretreatment with 0.1 U of PLase A2. After pretreatment of lung membranes with PLase A2, the number of beta-adrenoceptors was reduced by 25% compared with that in the control group, and adenylate cyclase activity stimulated by isoproterenol and forskolin were also reduced by 67 and 28%, respectively. PLase A2 had a minor effect on forskolin-stimulated activity as compared with isoproterenol-stimulated activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of age on bronchodilator responsiveness

The relationship between age and bronchodilator responsiveness (BDR) in children has not been studied using objective parameters. The aim of this study was to seek such a relationship in young asthmatic children using dose—response curves (DRC). Fourteen asthmatic subjects (age 3–9 years) with a forced expiratory volume in 1 sec (FEV₁) less than 80% predicted were studied after being trained to use a spirometer reliably. Each subject completed a DRC by inhaling 5 doses of salbutamol (albuterol) at 15 min intervals until a cumulative total of 6.84 mg of salbutamol had been administered. FEV₁, forced vital capacity (FVC), and forced expiratory flow at mid vital capacity (FEF_25?75) were measured before and after each nebulization. In addition, arterial oxygen saturation (Sa_O2) and heart rate (HR) were measured in some of the subjects. All lung function parameters, Sa_O2 and HR increased significantly between baseline and completion of the DRC. A significant age effect on BDR was detected in FEV₁ and FVC, with older children showing a greater response than young ones. The response had plateaued after the maximum dose in the younger but not in the older children. These findings suggest that the level of response to a bronchodilator increases significantly with increasing age in young asthmatics. © 1993 Wiley-Liss, Inc.     

The role of protein synthesis in polymorphonuclear leukocyte phagocytosis II.

Polymorphonuclear leukocytes collected from healthy human volunteers were treated with puromycin which inhibited protein synthesis in the cell. The neutrophils exhibited a marked decrease in phagocytosis after 1 h. The myeloperoxidase mediated conversion of iodide to a protein-bound form was also decreased. Hexosemonophosphate shunt activity remained similar for both puromycin treated PMN and control cells at 1 h. The results suggest that new protein synthesis is necessary to maintain PMN function at full capacity.     

Simvastatin treatment modifies polymorphonuclear leukocyte function in high-risk individuals: a longitudinal study

BACKGROUND: Although extensive experimental evidence supports a primary role of polymorphonuclear leukocytes (PMNs) in atherosclerosis, few data exist concerning the functional properties of these cells and their pharmacological modulation in high-risk individuals. OBJECTIVE: The production of the proinflammatory chemokine interleukin-8 (IL-8), migration and chemotaxis, and reactive oxygen species (ROS) generation were investigated in a longitudinal study in PMNs obtained from high-risk individuals during statin treatment. As a secondary endpoint we compared PMN function of high-risk patients with that of controls. METHODS AND RESULTS: PMNs were isolated from 21 high-risk individuals before treatment and 3 and 30 days after the beginning of simvastatin treatment, and from healthy controls. During treatment a significant reduction was observed both in resting (P = 0.009) and N-formyl-Met-Leu-Phe (fMLP)-stimulated (P = 0.008) IL-8 production, and in the chemotactic index (P = 0.038), whereas ROS generation did not significantly change. In comparison with cells from controls, PMNs obtained from patients before starting simvastatin treatment showed higher resting and fMLP-stimulated IL-8 release (P = 0.007 and P = 0.002, respectively) and ROS generation (resting, P = 0.009; and fMLP-stimulated, P = 0.046), whereas migration and the chemotactic index did not significantly differ. CONCLUSIONS: An activation of neutrophils is present in high-risk individuals, shown by the enhanced production of IL-8, and increased ROS generation. The 4-week statin treatment is able to reduce the cell capability to produce IL-8, and to decrease chemotaxis, thus affecting the proinflammatory properties of PMNs.