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Search Results: 1 - 10 of 410765 matches for " Soheir M El Nahas "
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Assignment of PCR markers to river buffalo chromosomes
Hanaa A Oraby, Soheir M El Nahas, H Anna de Hondt, Akmal El Ghor, Mohamed Samad
Genetics Selection Evolution , 1998, DOI: 10.1186/1297-9686-30-1-71
Abstract:
Mutagenic Potential of Radio Frequency Electromagnetic Fields
Magdy S. Aly,Mohamad B. Ashour,Soheir M. El Nahas,Othman E. Othman
Journal of Biological Sciences , 2002,
Abstract: The present study was conducted to determin the potential genetic damage of occupational exposure to EM field. The studied subjects are engineers and air traffic controllers exposed to radio frequency emitted from different instruments. Lymphocytes of exposed and control individuals were analyzed for structural and numerical chromosomal aberrations, sister chromatid exchanges, mitotic activity and cell kinetics. Cells with structural chromosomal aberrations were significantly increased in both engineers and air traffic controllers (P<0.001). Also, The number of aberrant cells with total numerical aberrations increased significantly in both exposed groups (P<0.001). Numerical aberrations were mainly hypodiploidy. The frequencies of SCEs in engineers and air traffic controllers were slightly increased over the control but this increase was not statistically significant. A decrease in mitotic activity was reported in EM field exposed engineers and air traffic controllers at statistically significant levels of P<0.01 and P<0.001, respectively. Exposure to EM field did not affect the cell kinetics in engineers and air traffic controllers.
Genotoxicity and Cytotoxicity of the Anticancer Drugs Gemcitabine and Cisplatin, Separately and in Combination: in vivo Studies
Magdy S. Aly,Mohamad B. Ashour,Soheir M. El Nahas,Mona A. F. Abo Zeid
Journal of Biological Sciences , 2003,
Abstract: Both gemcitabine (2`,2`-difluorodeoxycytidine, dFdC) and cisplatin (cis-diammine-dichloroplatinum) have significant anticancer activity against ovarian, head and neck and non-small cell lung cancer (NSCLC). dFdC can be incorporated into DNA and RNA and inhibit DNA repair, while cisplatin can form Pt-DNA abducts. Because of differences in mechanisms of action and toxicity profiles, combination of the two drugs has enormous clinical potential. The combination of both is increasingly applied in clinical oncology. In this study, the genotoxic effects of cisplatin and gemcitabine separately and in combination were detected in the male mice bone marrow cells. Four doses were used for each drug. In CDDP experiments 6, 12, 24 and 36 mg kg ̄1 body weight were used. For dFdC 40, 50, 60 and 80 mg kg ̄1 body weight were used. Three drug combination doses were used: 4 mg kg ̄1 body wt. CDDP, 20 mg kg ̄1 body wt. dFdC; 6 mg kg ̄1 body wt. CDDP, 20 mg kg ̄1 body wt. dFdC; and 8 mg kg ̄1 body wt. CDDP, 20 mg kg ̄1 body wt. dfdC. In the drug combination experiments, CDDP were injected 4 hours prior to dfdC. Total chromosomal aberrations and sister chromatid exchanges (SCEs) frequencies were increased after exposure to combined drugs compared to exposure to each drug separately. Both single and combined drugs decreased the mitotic activity of the cells and induced a cell cycle delay with increasing the doses. In conclusion, the potentiation in chromosomal aberrations and sister chromatid exchanges formation might be a result of the inhibition of DNA repair by dFdC. The synergism between dFdC and CDDP appears to be mainly due to an increase in Pt-DNA adduct formation possibly related to changes in DNA due to dFdC incorporation into DNA.
A Single Institutional Phase II Randomized Trial of Whole Brain Radiation Therapy with or without Irinotecan for the Treatment of Brain Metastases from Solid Tumours  [PDF]
Soheir S. Ismail, Soheir H. Mahmoud, Dina A. Salem, Ahmed E. Essa, Diaa El-Din M. Sherif
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.610094
Abstract: Background: The relatively suboptimal results of whole brain radiation therapy (WBRT) alone in eradication of brain metastases and an attempt to improve outcomes with WBRT have led to studies combining radiotherapy with chemotherapy drugs that could act as radiosensitizers with a rationale of improving local tumor control. Materials and Methods: This randomized phase II study evaluated the use of Irinotecan concomitant with 37.5 Gray (Gy) of WBRT in 2.5 Gy daily fractions × 5 days each week for 3 weeks versus Whole WBRT alone in patients with brain metastasis (BM) from solid tumors. Fifty patients were randomized to receive either WBRT alone or concomitant with three irinotecan IV infusions 80 mg/m2, 2 hrs before RT on days 1, 8, and 15. Results: The objective response rate (ORR) was significantly improved in patients receiving Irinotecan with radiotherapy versus radiotherapy alone (48% vs. 28%; p = 0.048). The median time to progression of brain metastasis was significantly longer in the irinotecan and WBRT arm as compared to the WBRT arm (8 vs. 5 months; p < 0.001). There was no significant difference in survival between treatment arms (p = 0.361). Irinotecan with radiotherapy was generally well tolerated and did not interfere with the delivery of WBRT. Conclusions: Irinotecan concomitant with WBRT was well tolerated and significantly improved local control of BM compared with WBRT alone. These findings require confirmation in a phase III trial with addition of quality of life assessment.
Natural History of Chronic Kidney Disease Stages 2-4
MEA Yousi, M El Nahas
Arab Journal of Nephrology and Transplantation , 2010,
Abstract: Introduction: Chronic kidney disease (CKD) is a worldwide problem. The majority of patients in stage 3-5 CKD progress relentlessly to end stage renal disease (ESRD). This study aimed to measure the rate of decline in kidney function among a group of CKD patients and to examine risk factors associated with disease progression. Methods: This is a retrospective study of 300 CKD patients in stages 2-4, that were randomly selected from patients who were on regular follow up in Sheffield kidney institute (SKI), Sheffield, UK, up to June 2007. Patients whose estimated glomerular filtration rate (GFR) declined by more than 1 ml/min/year according to the MDRD formula during a 5-year follow up period were classified as progressors. Baseline parameters that may be associated with a more rapid decline in GFR were evaluated. Results: Males constituted 57.7% of the study population, one third of patients were older than 65 years of age, 93% were white and 39.7% were diabetic. The study showed that 52.7% of patients had a progressive course of CKD. Gender, old age, ethnicity and diabetic status were not significantly different between progressors and non-progressors. Progressors tended to have higher 24-hour urinary protein excretion (2.6 ± 3.6 versus 1.8 ± 3.5 g/dl) and higher blood pressures measurements at baseline that did not reach statistical significance. The slope of reciprocal serum creatinine (1/S. Cr) was significantly and negatively correlated with systolic blood pressure (SBP). It was also significantly and negatively correlated to baseline serum creatinine. Conclusion: Almost half the patients had a rate of decline in estimated GFR that exceeded 1 ml/min/year and were classified as progressors.
Risk factors of hyperparathyroidism in advanced stages of chronic kidney disease
El Kossi M,Rana A,El Nahas M
Saudi Journal of Kidney Diseases and Transplantation , 2009,
Abstract: The pathogenesis of renal osteodystrophy is not clearly defined. We evaluate in this study the potential effect of demographic and biochemical markers on parathormone (PTH) level in patients with chronic kidney disease (CKD) stages 4 and 5. We retrospectively studied 138 patients with CKD stages 4 and 5 selected from the database of the Sheffield Kidney Institute in the interval from 1996 to 2005. All patients had baseline as well as follow-up levels of PTH, adjusted serum calcium, phosphate, calcium phosphorus product, albumin, bicarbonate and estimated glomerular filtration rate (eGFR). At baseline, serum albumin, eGFR and adjusted serum calcium levels signi-ficantly negatively correlated with PTH serum levels. Adjusted serum calcium levels at last follow-up remained a significant negative predictor of PTH levels; however, baseline PTH levels demons-trated a significant positive correlation with final serum PTH levels. This study high lights the significance of serum PTH levels at presentation on the long-term effect of parathyroid gland function. This reinforces the need for early intervention to achieve optimal control of hyperpara-thyroidism in CKD patients.
A Randomized Fully Polynomial-time Approximation Scheme for Weighted Perfect Matching in the Plane
Yasser M. Abd El-Latif,Salwa M. Ali,Hanaa A.E. Essa,Soheir M. Khamis
International Journal of Advanced Computer Sciences and Applications , 2012,
Abstract: — In the approximate Euclidean min-weighted perfect matching problem, a set V of 2n points in the plane and a real number 0 are given. Usually, a solution of this problem is a partition of points of V into n pairs such that the sum of the distances between the paired points is at most (1 )times the optimal solution.In this paper, the authors give a randomized algorithm which follows a Monte-Carlo method. This algorithm is a randomized fully polynomial-time approximation scheme for the given problem. Fortunately, the suggested algorithm is a one tackled the matching problem in both Euclidean nonbipartite and bipartite cases.The presented algorithm outlines as follows: With repeating 1/ times, we choose a point from V to build the suitable pair satisfying the suggested condition on the distance. If this condition is achieved, then remove the points of the constructed pair from V and put this pair in M (the output set of the solution). Then, choose a point and the nearest point of it from the remaining points in V to construct a pair and put it inM . Remove the two points of the constructed pair from V and repeat this process until V becomes an empty set. Obviously, this method is very simple. Furthermore, our algorithm can be applied without any modification on complete weighted graphs K mand complete weighted bipartite graphs Kn,n, where n,m 1and m is an even.
Synthesis and Photophysical Property Studies of the 2,6,8-Triaryl-4-(phenylethynyl)quinazolines
Malose Jack Mphahlele,Hugues Kadem Paumo,Ahmed M. El-Nahas,Morad M. El-Hendawy
Molecules , 2014, DOI: 10.3390/molecules19010795
Abstract: The 2-aryl-6,8-dibromo-4-chloroquinazolines derived from the 2-aryl-6,8-dibromoquinazolin-4(3 H)-ones were subjected to the Sonogashira cross-coupling with terminal acetylenes at room temperature to afford novel 2-aryl-6,8-dibromo-4-(alkynyl)quinazoline derivatives. Further transformation of the 2-aryl-6,8-dibromo-4-(phenylethynyl)quinazolines via Suzuki-Miyaura cross-coupling with arylboronic acids occurred without selectivity to afford the corresponding 2,6,8-triaryl-4-(phenylethynyl)quinazolines. The absorption and emission properties of these polysubstituted quinazolines were also determined.
Karyological Studies on the Solanaceae
Awatif I. El-Nahas,Sayed. F. Khalifa,Maged. M. Abou-El-Enain
Pakistan Journal of Biological Sciences , 2000,
Abstract: Comparative karyological studies for 23 taxa of the Solanaceae have been presented and their taxonomic aspects are discussed. It was concluded that the origin of the family is a taxon with basic chronomosome number of x = 7 or 8 which gave rise to other taxa by aneuplodiy and polyploidy. Nictiana alata and Browallia viscosa are found to be less evolved than the other species studied. Concerning the total form percentage (TF%) a reverse trend towards increasing the degree of karyotype symmetry with advancing evolution is concluded.
50 GHz Spaced 4 × 40 Gbit/s WDM Transmission over 700 km Using 6 ps Bandlimited RZ Signals  [PDF]
Mousaab M. Nahas
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.13023
Abstract: In this paper, we present 50 GHz spaced 4 ×40 Gbit/s WDM transmission over 700 km using SMF-based Effective Area Enlarged Positive Dispersion Fiber in a recirculating loop. The paper uses bandlimited RZ signals and shows that transmission distance of 700 km can be achieved with BER ≤ 10-9 using 6 ps pulsewidth for each data signal. To attain this, optical filters with sharp transmission characteristics are used in both transmitter and receiver. The results demonstrated in this paper are based on simulation, and the author believes the propagation distance reached in the paper is the longest distance achieved for such system.
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