study on the possible protective effect of some antioxidants in cigarette smoke-induced oxidative stress in the rat

The design of the present work was set to detect how smoking challenges the antioxidant defense system and to evaluate the possible protective effects of three antioxidants namely, vitamin C, vitamin E and sodium selenite, given either singly or in combination, on oxidative stress induced by cigarette smoke [CS]. The study also examined the effect of CS exposure on endothelin-1 [ET-1] production and the influence of the probed antioxidants. Sixty rats were used in the current study, they were divided into 6 groups, each of ten animals. Group I served as normal controls. Rats in group II were exposed to cigarette smoke for 15 minutes, twice daily, 6 days/week for 8 weeks. Rats in group III, IV and V received vitamin C [75 mg/kg.b.wt], vitamin E [150 mg/kg.b.wt] and sodium selenite [100 micro g/kg b.wt], orally, half an hour prior to cigarette smoke exposure. Group VI received a combination of vitamin C 25 mg/kg b.wt, vitamin E 50 mg/kg b.wt and sodium selenite 33.3 micro g/kg b.wt.], orally, half an hour prior to CS exposure. At the end of the experiment, plasma samples were withdrawn for plasma ET-1 estimation. Liver homogenates were prepared for determination of malondialdhyde [MDA], glutathione peroxidase [GPx], superoxide dismutase [SOD] and reduced glutathione [GSH] levels by biochemical methods. Cigarette smoke exposure was associated with increased oxidative stress as manifested by a significant increase in MDA level and a significant decrease in GSH concentration, GPx and SOD activities. Administration of vitamin C, vitamin E, Na selenite or the antioxidant combination produced a significant decrease in oxidative stress, in variable degrees, as manifested by a significant decrease in MDA level and significant increase in GSH concentration, GPx and SOD activities. The previous advantageous effects were more pronounced with the use of the antioxidant combination. This may be explained by the interaction between these antioxidants, working together in a network, recycling each other and thus creating an effective antioxidant defense system. Data also revealed that cigarette smoke exposure for 8 weeks, did not significantly affect plasma ET-1 level. A significant rise in plasma ET-1 level was only found in the selenium and combined antioxidant-supplemented groups. Supplementation with an antioxidant combination offers protection to macromolecules better than that offered by a single antioxidant, in CS-induced oxidative stress

Effect of furosemide on several agonists induced contractions in isolated guinea pig trachealis muscle and on allergen sensitized guinea pigs

To investigate the possible inhibitory effect of the loop diuretic, furosemide, on guinea pig trachealis muscle contractions induced by EFS, Ach, KCl and H. The study was also aiming at investigating the possible prophylactic effect of furosemide on specific AHR induced by allergen challenge of actively sensitized guinea pigs. In vitro study showed that atropine was noted to inhibit EFS [0.5 - 50 Hz] induced contractions which were inhibited by furosemide 1 - 100 muM] with more inhibition at low frequency of stimulation. Furosemide had no effect on either Ach nor KCl induced contractions, but it inhibited H induced contraction particularly at the latter low concentration. In vivo study showed that furosemide protected the sensitized animals against the specific AHR induced by allergen challenge. The protective index was observed as delay in the onset of dyspneic convulsions and degranulation of mast cells as examined histologically

Effect of ramipril [HOE-498] bisoprolol and propranolol on isoproterenol-induced myocardial necrosis

The present study was conducted to investigate and compare the possible protective effect of ramipril, a new angiotensin converting enzyme inhibitor [ACEI]; bisoprolol, a new B[1] cardioselective blocker; and propranolol on isoproterenol induced myocardial necrosis. Male albino rats were pretreated with 0.5 mg/kg body weight of ramipril intraperitneally [IP] on four seccessive days. The same animals were given 100 mg/kg body weight isoproterenol sub-cutaneously [SC], on the third and fourth days of the study. The same procedure was repeated with bisoprolol, 0.2 mg/kg body weight IP and propranolol, 0.5 mg/kg body weight intramuscularly [IM]. Twenty-four hours after the 2nd injection of isoproterenol blood samples were taken from orbital plexus. Then the animals were decapitated, hearts were separated and weighed. Isoproterenol caused a significant increase in heart weight, creatine phosphokinase [CPK] activity, lactate dehydrogenase [LDH], aspartate aminotransferase [ASAT] and alanine aminotransferase [ALAT]. Pretreatment of the animals with ramipril reduced significantly all the enzymes studied. Pretreatment with bisoprolol led to a significant reduction in the heart weight, CPK and LDH activities. Propranolol pretreated animals did not exhibit any significant change in the parameters tested as compared to the isoproterenol group

Study of the influence of ranitidine and phenylbutazone on oral iron absorption in rabbits

The present study aimed at evaluating the effect of prolonged oral administration [10 days] of ranitidine hydrochloride [10 mg/kg] and phenylbutazone [100 mg/kg] along and with ferrous sulfate [10 mg/kg], on the bioavailability of iron for intestinal absorption. Also, post absorption plasma iron tolerance curve was done to all groups. Fifty adult male rabbits were arranged into a control group, a ranitidine group and a phenylbutazone group. Ranitidine produced a significant decrease in plasma iron level when used alone [24.60%] as well as when given simultaneously with ferrous sulfate [12.82%], while phenylbutazone whether given alone or with ferrous sulfate produced a statistically insignificant rise plasma iron [6.32% and 12.90%, respectively]

Effect of Ca++ chaxrnel blocking agents on experimental hyperthyroidi in the dog

This work was designed to study the effect of Ca++ channel blockers [verapamil and nifedipine] on hormonal release and actions in hyperthyroidistn. In hyperthyroid crisis, intravenous verapamil decreased serum tniodothyronine [T[3]], blood pressure, heart rate and double product cardiac output index and succeeded to reduce the encountered supraventnicular and ventricular arrhythmias. Nifedipine decreased the blood pressure and double product index, yet it did not induce any significant effect on thyroid honones or blood lipids. In chronic hyperthyroidiam, verapamil increased serum lipids and controlled nearly all cardiovascular complications of the disease. Nifedipine increased both serum triiodothyronine and tetraiodothyronine [Thyroxine, T[4]], as yell as free fatty acids [FFA]. It controlled hyperthyroid hypertension, but failed to control the rest of the existing cardiovascular ccniplications

Effects of Ca++ channel blocking agents on pituitary thyroid hormones, serum lipids and cardiovascular functions in euthyroid dogs

The effect of verapamil and mifedipine was studied in euthyroid dogs to detect whether these drugs alter pituitary-thyroid output and/or actions. Verapamil induced a significant decrease of serum TSH, T[3] and T[4] as well as significant increase of serum lipids. It also exhibited a bradycardiac action. Nifedipine decreased only serum T[3] and induced a significant increase in serum FFA and total cholesterol. It also led to a decrease in diastolic pressure and an increase in heart rate

Some metabolic effects of prolonged administration of clonidine hydrochloride in experimental animals [rabbits]

The present work was carried out on twenty male rabbits to study the prolonged effect of clonidine hydrochloride on plasma glucose, free fatty acids, sodium and potassium ions. Clonidine orally was given daily for six weeks. Blood samples were collected every forteen days. After two weeks there was a significant rise in plasma free fatty acids and plasma sodium and no changes in plasma glucose and potassium. Four weeks under clonidine intake plasma free fatty acids and plasma sodium were still high, while plasma glucose and potassium started to show a significant rlse. At the end of the experiment [6 weeks] all these parameters returned back to values close to those of the control. These results indicate that clonidine initially acts as a hyperglycemic and lipolytic agent. Also, it causes an initial sodium retention