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Khayyal, M. T., M. A. El-Ghazaly, and A. S. el-Khatib, "Mechanisms involved in the antiinflammatory effect of propolis extract.", Drugs under experimental and clinical research, vol. 19, issue 5, pp. 197-203, 1993. Abstract

Propolis is a natural product produced by the honey bee. The extract contains amino acids, flavanoids, terpenes and cinnamic acid derivatives. In various in vitro models propolis extract was shown to inhibit platelet aggregation and to inhibit eicosanoid synthesis, suggesting that it might have potent antiinflammatory properties. A 13% aqueous extract was tested orally in three dose levels (1, 5 and 10 ml/kg) on the carrageenan rat paw oedema model and on adjuvant-induced arthritis in rats. In both models, the extract showed potent dose-related antiinflammatory activity, which compared well with that of diclofenac (as a reference standard). The extract was then tested on an isolated sensitized guinea pig lung preparation to study its effect on the release of prostaglandins, leukotrienes and histamine. It is concluded that propolis extract has potent antiinflammatory properties in vivo. Its activity can be well correlated with its effects on the release of various mediators of inflammation.

Khayyal, M. T., M. A. El-Ghazaly, A. S. el-Khatib, A. M. Hatem, P. J. F. de Vries, S. el-Shafei, and M. M. Khattab, "A clinical pharmacological study of the potential beneficial effects of a propolis food product as an adjuvant in asthmatic patients.", Fundamental & clinical pharmacology, vol. 17, issue 1, pp. 93-102, 2003 Feb. Abstract

The aqueous extract of propolis has been formulated as a nutritional food product and administered, as an adjuvant to therapy, to patients with mild to moderate asthma daily for 2 months in the framework of a comparative clinical study in parallel with a placebo preparation. The diagnosis of asthma was made according to the criteria of patient classification of the National Institutes of Health and Global Initiative for Asthma Management. At inclusion, the pulmonary forced expiratory volume in the first second (FEV1) as a percentage of the forced vital capacity (FVC) was more than 80% in mild persistent cases, and between 60 and 80% in moderate persistent cases, showing an increase in the degree of reversibility of > 15% in FEV1. All patients were on oral theophylline as controller therapy, none was receiving oral or inhaled corticosteroids, none had other comorbidities necessitating medical treatment, and all were from a middle-class community and had suffered from asthma for the last 2-5 years. Twenty-four patients received the placebo, with one drop-out during the study, while 22 received the propolis extract, with no drop-outs. The age range of the patients was 19-52 years; 36 were male and 10 female. The number of nocturnal attacks was recorded on a weekly basis, while pulmonary function tests were performed on all patients at the beginning of the trial, 1 month later and at the termination of the trial. Immunological parameters, including various cytokines and eicosanoids known to play a role in asthma, were measured in all patients at the beginning of the trial and 2 months later. Analysis of the results at the end of the clinical study revealed that patients receiving propolis showed a marked reduction in the incidence and severity of nocturnal attacks and improvement of ventilatory functions. The number of nocturnal attacks dropped from an average of 2.5 attacks per week to only 1. The improvement in pulmonary functions was manifested as a nearly 19% increase in FVC, a 29.5% increase in FEV1, a 30% increase in peak expiratory flow rate (PEFR), and a 41% increase in the forced expiratory flow rate between 25 and 75% of the vital capacity (FEF25-75). The clinical improvement was associated with decreases by 52, 65, 44 and 30%, respectively, of initial values for the pro-inflammatory cytokines tumor necrosis factor (TNF)-alpha, ICAM-1, interleukin (IL)-6 and IL-8, and a 3-fold increase in the 'protective' cytokine IL-10. The levels of prostaglandins E2 and F2alpha and leukotriene D4 were decreased significantly to 36, 39, and 28%, respectively, of initial values. Patients on the placebo preparation showed no significant improvement in ventilatory functions or in the levels of mediators. The findings suggest that the aqueous propolis extract tested is potentially effective as an adjuvant to therapy in asthmatic patients. The benefits may be related to the presence in the extract of caffeic acid derivatives and other active constituents.

Khayyal, M. T., M. El-Ghazaly, A. S. el-Khatib, and A. Hatem, "Tolerability of mofebutazone in asthmatic patients.", International journal of clinical pharmacology research, vol. 15, issue 4, pp. 145-51, 1995. Abstract

Twenty-seven human volunteer asthmatic patients were each given one tablet of mofebutazone (300 mg) twice daily for 15 days. Pulmonary ventilatory function test (forced expiratory volume test) as well as bronchoalveolar lavage (BAL) were performed one day before initiation of treatment and one day after completion of the course; in the BAL, prostaglandin E2 (PGE2), prostaglandin F2alpha (PGF2alpha) and leukotrienes (LTs) were also estimated. It was found that there was no increase in the incidence or severity of the asthmatic attacks during the course of mofebutazone treatment. The drug tended to improve the tested pulmonary ventilatory functions or at least to leave them unchanged. All the mofebutazone-treated individuals showed a dramatic reduction in the concentrations of PGE2, PGF2alpha and LTs in their BAL, but there was no consistent correlation between the extent of reduction and the degree of benefit or worsening sustained by any individual patient. It is evident from the present study that mofebutazone has shown good tolerability which was associated with an improvement in the pulmonary ventilatory functions, a fact that would seem to advocate the use of this non-steroidal antiinflammatory drug (NSAID) in asthmatic patients whenever a need for such therapy becomes necessary.

Khayyal, M. T., A. S. el-Khatib, M. El-Ghazaly, and A. Hatem, "Inhibition of leukotriene release by mofebutazone: a possible clinical advantage.", International journal of clinical pharmacology research, vol. 13, issue 5, pp. 255-61, 1993. Abstract

The isolated perfused lung preparation from actively sensitized guinea-pigs was used; after it was challenged with antigen, mediators such as histamine, prostaglandins and leukotrienes were released into the lung effluent. It was found that treatment of the perfused lungs before and during challenge with mofebutazone (10 micrograms/ml) inhibited the immunological release of prostaglandins as well as leukotrienes. Phenylbutazone, on the other hand, at the same dose level inhibited the release of prostaglandins, whereas the release of leukotrienes was much less affected by the drug. Histamine release was not altered by either drug. When clinically mofebutazone tablets (300 mg) were given as an analgesic twice daily for 15 days to a number of asthmatic volunteers including 3 aspirin-sensitive individuals, there was no increase in the incidence or intensity of the asthmatic attacks, even in the aspirin-sensitive patients. Pulmonary ventilatory functions which showed a certain obstructive pattern were not worsened by the treatment and even tended to be somewhat improved.

M
Mahran, L. G., A. S. el-Khatib, A. M. Agha, and M. T. Khayyal, "The protective effect of aqueous propolis extract on isolated rat hepatocytes against carbon tetrachloride toxicity.", Drugs under experimental and clinical research, vol. 22, issue 6, pp. 309-16, 1996. Abstract

The protective effect of honeybee aqueous propolis extract (APE) against the hepatotoxicity of carbon tetrachloride was investigated using isolated liver-cell suspensions as the experimental model. Various concentrations of the extract were preincubated with the hepatocyte suspensions for 30 min before being subjected to the hepatotoxin for a further 30 min. The hepatocyte toxicity was assessed using three parameters, namely, the release of lactate dehydrogenase, the formation of lipid peroxides and the depletion of intracellular reduced glutathione. It was found that a dose-related protection against the induced cell injury was conferred by APE as evidenced by its inhibitory influence on the changes induced by CCl4 on the measured parameters. The hepatocyte protective effect of APE is probably a result of its antioxidant and free-radical-scavenging properties which in turn help to maintain the intracellular level of reduced glutathione.

Mansour, M. A., O. T. Ginawi, T. El-Hadiyah, A. S. el-Khatib, O. A. Al-Shabanah, and H. A. Al-Sawaf, "Effects of volatile oil constituents of Nigella sativa on carbon tetrachloride-induced hepatotoxicity in mice: evidence for antioxidant effects of thymoquinone.", Research communications in molecular pathology and pharmacology, vol. 110, issue 3-4, pp. 239-51, 2001. Abstract

Effects of the volatile oil constituents of Nigella sativa, namely, thymoquinone (TQ), p-cymene and alpha-pinene, on carbon tetrachloride (CCl4-indued acute liver injury were investigated in mice. A single dose of CCl4 (15 microl/Kg i.p.) induced hepatotoxicity 24 h after administration manifested biochemically as significant elevation of the enzymes activities of serum alanine transaminase (ALT, EC:2.6.1.2), asparate transaminase (AST, EC:2.6.1.1) and lactate dehydrogenase (LDH, EC: 1.1.1.27). The toxicity was further evidenced by a significant decrease of non-protein sulfhydryl(-SH) concentration, and a significant increase of lipid peroxidation measued as malondialdhyde (MDA) in the liver tissues. Administration of different doses of the TQ (4, 8, 12.5, 25 and 50 mg/Kg i.p.) did not alter the chosen biochemical parameters measured, while higher doses of TQ were lethal. The LD50 was 90.3 mg/Kg (77.9-104.7, 95% CL). Pretreatment of mice with different doses of TQ 1 h before CCl4 injection showed that the only dose of TQ that ameliorated hepatotoxicity of CCl4 was 12.5 mg/Kg i.p. as evidenced by the significant reduction of the elevated levels of serum enzymes as well as hepatic MDA content and significant increase of the hepatic nonprotein sulfhydryl(-SH) concentration. Treatment of mice with the other volatile oil constituents, p-cymene or alpha-pinene did not induce any changes in the serum ALT measured. In addition, i.p. administration of these compounds 1 h before CCl4 injection, did not protect mice against CC4-induced hepatotoxicity. The results of the present study indicate that TQ (12.5 mg/Kg, i.p.) may play an important role as antioxidant and may efficiently act as a protective agent against chemically-induced hepatic damage. In contrast, higher doses of TQ were found to induce oxidative stress leading to hepatic injury.

Mansour, S. M., A. K. Bahgat, A. S. El-Khatib, and M. T. Khayyal, "Ginkgo biloba extract (EGb 761) normalizes hypertension in 2K, 1C hypertensive rats: role of antioxidant mechanisms, ACE inhibiting activity and improvement of endothelial dysfunction.", Phytomedicine : international journal of phytotherapy and phytopharmacology, vol. 18, issue 8-9, pp. 641-7, 2011 Jun 15. Abstract

The 2 kidney, 1-clip (2K, 1C) model of hypertension was used to investigate the potential antihypertensive effect of a standardized leaf extract of Ginkgo biloba (EGb 761). Clipping of the renal artery resulted in gradual elevation of the systolic blood pressure (SBP) reaching a plateau after 4 weeks of surgery. Treatment of hypertensive rats with EGb 761 (60, 90, 180 mg/kg/day orally) was therefore started 4 weeks after surgery and continued for 3 weeks. This led to a dose-dependent reduction in SBP with no significant change in heart rate. Control hypertensive rats showed a significant elevation of total protein thiols (Pr-SHs level) in both clipped and non-clipped kidneys as well as in the serum. However, glutathione peroxidase (GSH-Px) activity was decreased in the clipped kidneys but elevated in the non-clipped ones and in the blood. The malondialdehyde (MDA) level was raised in clipped kidneys but not in non-clipped ones nor in the serum. Nitric oxide (NO level) and angiotensin converting enzyme (ACE) activity were increased in both clipped and non-clipped kidneys but not in the serum. Endothelium-dependent and -independent relaxation of aortic rings towards acetylcholine (Ach) and sodium nitroprusside (SNP) were impaired. Treatment with EGb 761 (180 mg/kg/day for 3 weeks) was associated with recovery of GSH-Px activity in clipped kidneys, inhibition of ACE activity in both kidneys and a reduction in the elevated NO level of the non-clipped kidneys, decreased responsiveness to the vasoconstrictor NE and improvement of endothelial function as evidenced by restoration of endothelium-dependent vasorelaxation induced by Ach. The observed beneficial effects of the EGb 761 may be attributed to different factors, including ACE inhibition and maintenance of cellular antioxidant capacity as well as preserving vascular reactivity towards endothelium-dependent and -independent vasodilators while inhibiting responses to vasoconstrictors.

Mansour, M., A. S. el-Khatib, and O. El-Ahmady, "INHIBITED GENERATION OF LEUKOTRIENES FROM STIMULATED HUMAN LEUKOCYTES BY THE AQUEOUS EXTRACT OF PROPOLIS", Bull. Fac. Pharm. Cairo Uni, vol. 33, issue 2, pp. 75-79, 1995.
Mansour, M. A., M. N. Nagi, A. S. El-Khatib, and A. M. Al-Bekairi, "Effects of thymoquinone on antioxidant enzyme activities, lipid peroxidation and DT-diaphorase in different tissues of mice: a possible mechanism of action.", Cell biochemistry and function, vol. 20, issue 2, pp. 143-51, 2002 Jun. Abstract

The present investigation focused, firstly, on the effects of oral administration of thymoquinone (TQ) on antioxidant enzyme activities, lipid peroxidation and DT-diaphorase activity in hepatic, cardiac and kidney tissues of normal mice. Superoxide dismutase (SOD; E.C:1.15.1.1), catalase (CAT; E.C:1.11.1.6), glutathione peroxidase (GSH-Px; E.C:1.11.1.9), glutathione-S-transferase (GST; E.C:2.5.1.18), and DT-diaphorase (E.C:1.6.99.2) enzyme activities in each tissue type were determined. Treatment of mice with the different doses of TQ (25, 50 and 100 mg kg(-1) day(-1) orally) for 5 successive days, produced significant reductions in hepatic SOD, CAT and GSH-Px activities. In addition cardiac SOD activity was markedly inhibited with the higher doses of TQ, (namely 50 and 100 mg kg(-1)). Moreover, TQ (100 mg kg(-1)) significantly reduced hepatic and cardiac lipid peroxidation as compared with the respective control group. Conversely, TQ (50,100 mg kg(-1)) and TQ (100 mg kg(-1)) enhanced cardiac and renal DT-diaphorase activity respectively. However, the selected doses of TQ neither produced any change in GST activity nor influenced reduced glutathione content in all tissues studied. TQ was tested, secondly, as a substrate for hepatic, cardiac and renal DT-diaphorase of normal mice in the presence of NADPH. Kinetic parameters for the reduction of TQ to dihydrothymoquinone (DHTQ) indicated that DT-diaphorase of different tissues can efficiently reduce TQ to DHTQ. K(m) and V(max) values revealed that hepatic DT-diaphorase exhibited the higher values, while the lower values were associated with renal DT-diaphorase. TQ and DHTQ were tested, thirdly, as specific scavengers for superoxide anion (generated biochemically) or as general scavengers for free radicals (generated photochemically). The results revealed that TQ and DHTQ acted not only as superoxide anion scavengers but also as general free radical scavengers. The IC(50) for TQ and DHTQ in biochemical and photochemical assays were in the nanomolar and micromolar range respectively. Our data may explain at least partly the reported beneficial in vivo protective effects of TQ through the combined antioxidant properties of TQ and its metabolite DHTQ.

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Raafat, S. N., R. M. Amin, M. M. Elmazar, M. M. Kattab, and A. El-Khatib, "The sole and combined effect of simvastatin and platelet rich fibrin as a filling material in induced bone defect in tibia of albino rats", Bone, vol. 711: Elsevier, pp. 12–34, 2018. Abstract
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Rasheed, N. A. O., N. S. El Sayed, and A. S. El-Khatib, "Targeting central $\beta$2 receptors ameliorates streptozotocin-induced neuroinflammation via inhibition of glycogen synthase kinase3 pathway in mice", Progress in Neuro-Psychopharmacology and Biological Psychiatry, vol. 86: Elsevier, pp. 65–75, 2018. Abstract
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Saleh, D. O., A. R. Bayoumi, W. I. El-Eraky, and A. S. El-Khatib, "Streptocin-induced vascular and biochemical changes in rats: Effects of rosiglitazone vs. metformin", Bulletin of Faculty of Pharmacy, Cairo University, vol. 51, pp. 131-138, 2013.
Saleh, D. O., S. A. El-Awdan, S. M. Nofel, W. I. El-Eraky, A. S. el-Khatib, and S. A. Kenawy, "ESTROGENS IMPROVE THE CARDIOVASCULAR ALTERATIONS IN FRUCTOSE-INDUCED INSULIN RESISTANT OVARIECTOMIZED RATS", Int. J. Pharm. Pharm. Sci, vol. 7, issue 7, pp. 241-247, 2015.
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