Phenothiazines inhibit copper and endothelial cell-induced peroxidation of low density lipoprotein. A comparative study with probucol, butylated hydroxytoluene and vitamin E

The effect of two phenothiazines, chlorpromazine (CPZ) and trifluoperazine (TFP) on the copper and endothelial cell-induced peroxidation of low density lipoprotein (LDL) has been studied and compared to that of drugs previously shown to protect LDL against peroxidation: probucol (PBC) and butylated hydroxytoluene (BHT). Incubation with CPZ or TFP inhibited in a dose-dependent manner LDL peroxidation induced either by copper ions or by cultured endothelial cells. Both the electrophoretic mobility and the thiobarbituric reactive substance content of LDL returned to almost normal values in the presence of 50 microM CPZ or TFP. The two studied phenothiazines also strongly inhibited the hydrolysis of LDL phosphatidylcholine which accompanies copper or endothelial cell-induced peroxidation of the particle. CPZ and TFP were as effective as PBC and BHT in inhibiting the LDL peroxidation. Whereas copper or endothelial cell-oxidized LDL were recognized and rapidly catabolized by mouse peritoneal macrophages, CPZ- or TFP-, as well as PBC- or BHT-treated LDL were not. Moreover, it was found that, in contrast to vitamin E, neither CPZ nor PBC reacted with model peroxy radicals formed by gamma irradiation of aerated ethanol. The possible mechanisms underlying this protective effect of phenothiazines against LDL oxidative modification are discussed.     

Structure-activity relationship of macrocyclic and linear gadolinium chelates: Investigation of transmetallation effect on the zinc-dependent metallopeptidase angiotensin-converting enzyme

Transmetallation between commercially available solutions of gadolinium (Gd) chelates and the zinc (Zn)-dependent angiotensin-converting enzyme (ACE) was investigated. In vitro, the strongest inhibitions were observed for the linear Gd complexes, Gd diethylene-triamine pentaacetic acid (DTPA) bis-methylamide (BMA) (IC₅₀ = .016 ± .006 mmol/1) and Gd-DTPA (IC₅₀ = .350 ± .034 mmol/1). The two macrocycles Gd tetraazacyclododecane tetraacetic acid (DOTA) and Gd-HP-DO3A were similar and 400 times less active than Gd-DTPA-BMA. These effects were mainly due to the presence of free ligand for DTPA and calcium (Ca) chelate in the case of DTPA-BMA because the addition of Zn²⁺ in the same quantities suppresses their inhibitory effects. In vivo, these two solutions of linear Gd chelates significantly inhibited ACE activity (Gd-DTPA: 67 ± 9% versus baseline; and Gd-DTPA-BMA: 73 ± 2% versus baseline at the clinical dose of .1 mmol/kg), whereas no significant effect was observed for the two macrocyclic chelates Gd-DOTA and Gd-HP-DO3A. Formulating the Gd chelate solution with either an excess of free ligand or Ca chelate (to decrease Gd³⁺ release) in the case of linear Gd chelate may have deleterious biologic consequences.     

Assessment of laboratory and field assays of sunlight-induced killing of mosquito larvae by photosensitizers

The effectiveness of light-induced killing of mosquito larvae in the presence of photosensitizers was studied with larvae of Aedes aegypti (L.), Anopheles stephensi (Liston), and Culex quinquefasciatus Say grown in the laboratory and of Cx. quinquefasciatus grown under field conditions. Tested photosensitizers included xanthene, chlorin, and porphyrin derivatives. All the larvae were treated at the fourth instar. Preliminary laboratory experiments showed a light-induced lethal effect of Rose Bengal (RB) on three species of mosquito larvae. Compared with other photosensitizers, RB seemed to be more efficient at even lower concentration than chlorin (e6) and chlorophyllin on Ae. aegypti larvae. Among the four porphyrin derivatives, i.e., chloroquinoline tetraphenyl propioamidoporphine, tetraphenyl porphine tetrasulfonate, hematoporphyrin (HP), and tetraphenylporphinepropionic acid porphine, HP was the only effective photosensitizer on Ae. aegypti larvae. The best conditions for field tests using RB were conducted on Cx. quinquefasciatus in Bobo-Dioulasso, Burkina Faso. The mortality induced by RB varied from 80 to 96% obtained with unfiltered cesspit water to 0.4 to 6.7% in cesspits with a heavy load of organic materials, thus providing the basis for further developments of this technique under field conditions.     

Oxidative Stress and Respiratory System: Pharmacological and Clinical Reappraisal of N-Acetylcysteine

The large surface area for gas exchange makes the respiratory system particularly susceptible to oxidative stress-mediated injury. Both endogenous and exogenous pro-oxidants (e.g. cigarette smoke) trigger activation of leukocytes and host defenses. These mechanisms interact in a “multilevel cycle” responsible for the control of the oxidant/antioxidant homeostasis. Several studies have demonstrated the presence of increased oxidative stress and decreased antioxidants (e.g. reduced glutathione [GSH]) in subjects with chronic obstructive pulmonary disease (COPD), but the contribution of oxidative stress to the pathophysiology of COPD is generally only minimally discussed. The aim of this review was to provide a comprehensive overview of the role of oxidative stress in the pathogenesis of respiratory diseases, particularly COPD, and to examine the available clinical and experimental evidence on the use of the antioxidant N-acetylcysteine (NAC), a precursor of GSH, as an adjunct to standard therapy for the treatment of COPD. The proposed concept of “multilevel cycle” helps understand the relationship between respiratory diseases and oxidative stress, thus clarifying the rationale for using NAC in COPD. Until recently, antioxidant drugs such as NAC have been regarded only as mucolytic agents. Nevertheless, several clinical trials indicate that NAC may reduce the rate of COPD exacerbations and improve small airways function. The most plausible explanation for the beneficial effects observed in patients with COPD treated with NAC lies in the mucolytic and antioxidant effects of this drug. Modulation of bronchial inflammation by NAC may further account for these favorable clinical results.     

Salmeterol/fluticasone propionate in a Single Inhaler Device versus theophylline+fluticasone propionate in patients with COPD

STUDY OBJECTIVES: The aim of this study was to compare the relative efficacy in terms of improvement in symptoms and lung function of salmeterol/fluticasone propionate (SLM/FP) combination administered through the Diskus inhaler versus theophylline (THEO) added to FP Diskus in patients with stable chronic obstructive pulmonary disease (COPD). METHODS AND MEASUREMENTS: Eighty patients were randomized to receive 4 months of treatment in one of two treatment groups: (1) fixed combination of SLM 50 microg and FP 500 microg Diskus, 1 inhalation twice daily; or (2) FP Diskus 500 microg, 1 inhalation twice daily, plus oral titrated THEO twice daily. Patients attended the clinic before and after 4, 8, 12 and 16 weeks of treatment for evaluations of pulmonary function, and dyspnea, which was assessed using an analogic visual scale. Also the supplemental salbutamol use was measured. RESULTS:. Sixty-six patients completed the 4-month treatment period: 37 patients receiving SLM/FP and 29 patients receiving THEO+FP. Patients were withdrawn for various reasons, the most common of which were poor compliance with the protocol, exacerbation and GI events. A gradual increase in FEV(1) was observed with each treatment. Maximum significant increases in FEV(1) over baseline values that were observed after 4 months of treatment were as follows: SLM/FP 0.172 l (95% CI: 0.084-0.260) and THEO+FP 0.155 l (95% CI: 0.054-0.256). SLM/FP experienced significantly (p<0.05) greater improvements in dyspnea, and required significantly fewer supplemental salbutamol treatments than the THEO+FP group. CONCLUSIONS: Our results suggest that SLM/FP combination may provide substantial benefits in both physiologic and clinical outcomes in symptomatic patients with COPD. It also causes a more effective control than THEO+FP.     

Estrogens inhibit copper and cell-mediated modification of low density lipoprotein.

The effects of estrogens on LDL modification by copper ions, U 937 monocyte-like cells or endothelial cells was studied by determination of the lipid peroxidation product content and measurement of the relative electrophoretic mobility. The presence of estradiol, estriol and estrone inhibited LDL oxidation in a dose-dependent manner in the range of concentrations from 5 to 50 microM. In the case of oxidation by Cu2+, the decreasing order of efficiency was: estradiol, estriol, estrone. In monocyte-induced oxidation, the protective effect of estrogens was more marked, and the order of efficiency was the same, except that estrone was as active as estriol. Pretreatment of monocyte cells with estrogens also inhibited the subsequent modification of LDL by these cells, tested in the absence of the hormones. Testosterone had no effect in all the studied systems. Furthermore, the degradation by J774 macrophage like cells of LDL modified either by Cu2+ or monocytes was markedly reduced when modification has been performed in the presence of estrogens. Since oxidative modification of LDL is believed to be involved in the appearance of atherosclerotic plaques, this effect of estrogens might be related to their protective action against atherosclerosis.     

The functional impact of adding salmeterol and tiotropium in patients with stable COPD

The aim of this double-blind, double-dummy, crossover, randomised, pilot study was to explore the acute effects of adding salmeterol and tiotropium in patients with stable COPD. A total of 20 outpatients with stable COPD were enrolled. Single doses of 18-microg tiotropium, 50-microg salmeterol, and 18-microg tiotropium+ 50-microg salmeterol were given. Serial measurements of forced expiratory volume in 1 s (FEV1) were performed over 24h. The mean maximum increases in FEV1 from pre-dosing value on each of the dosing days were 0.165l (95% CI: 0.098-0.232) for tiotropium, 0.241 l (95% CI: 0.151-0.332) for salmeterol, and 0.290 l (95% CI: 0.228-0.353) for the combination and occurred 4 h after inhalation of tiotropium or salmeterol and 3 h after the combination. At 12h, the mean increases in FEV1 from pre-dosing value were 0.071 l (95% CI: 0.001-0.141; P = 0.047) for tiotropium, 0.069 l (95% CI: 0.018-0.120; P = 0.010) for salmeterol, and 0.108 l (95% CI: 0.047-0.170; P = 0.001) for the tiotropium + salmeterol combination. Only the difference between salmeterol and tiotropium + salmeterol was statistically significant (P = 0.009). At 24h, the mean FEV1 value was still higher than the mean pre-dosing value for tiotropium (0.042 l; 95% CI: -0.012-0.097; P=0.119) and the tiotropium+salmeterol combination (0.051 l; 95% CI: 0.01 5-0.087; P = 0.007), but not for salmeterol alone (-0.013 l; 95% CI: -0.041-0.014; P = 0.324). The FEV1 area under the curve (AUCs0-12h) were 1.657 l (95% CI: 1.152-2.162) for tiotropium, 2.068 (95l CI: 1.385-2.752) for salmeterol, and 2.541 l (95% CI: 1.954-3.129) for tiotropium + salmeterol. Only the difference between tiotropium and the tiotropium +salmeterol combination was statistically significant (P = 0.01). The FEV1 AUCs0-24h were 2.854 l (95% CI: 1.928-3.780) for tiotropium, 2.786 l (95% CI: 1.913-3.660) for salmeterol, and 3.640 l (95% CI: 2.674-4.605) for tiotropium + salmeterol. ALL differences between treatments were not statistically significant (P> 0.05). These results seem to indicate that the use of the tiotropium + salmeterol combination is more efficacious than the single agents alone, but the once-daily administration of the two drugs is inadvisable due to the broncholytic profile of salmeterol.     

Intrafamilial phenotypic variability in four families with Anderson‐Fabry disease

We analysed the clinical history of 16 hemizygous males affected by Anderson‐Fabry Disease, from four families, to verify their intrafamilial phenotypic variability. Seven male patients, ranging from 26 to 61 years of age, died, whereas nine (age range 23–55) are alive. Eleven patients have undergone enzyme replacement therapy (ERT) for a period of 5–10 years. We have found a wide range of intrafamilial phenotypic variability in these families, both in terms of target‐organs and severity of the disease. Overall, our findings confirm previous data from the literature showing a high degree of intrafamilial phenotypic variability in patients carrying the same mutation. Furthermore, our results underscore the difficulty in giving accurate prognostic information to patients during genetic counselling, both in terms of rate of disease progression and involvement of different organs, when such prognosis is solely based on the patient's family history.