Showing papers by "Cairo University published in 2001"
Book•
11 Apr 2001TL;DR: This book discusses process monitoring with Elastic and Electromagnetic Waves, and describes the properties of Electromagnetism and its applications in particle-Fluid Interactions and Soil Behavior.
Abstract: PART ONE: INTRODUCTION. Chapter 1: Materials And Scales. PART TWO: PARTICULATE MATERIALS. Chapter 2: Characterization Of Particles And Particulate Media. Chapter 3: Particle-Fluid Interactions. Chapter 4: Load-Deformation Behavior. Chapter 5: Conduction And Diffusion - Soil Behavior. PART THREE: ELASTIC WAVES AND SOILS. Chapter 6: Elastic Waves In The Continuum. Chapter 7: Elastic Waves In Particulate Media. Chapter 8: Velocity And Attenuation: Data And Empirical Relations. Chapter 9: Laboratory Measurement Methods. PART FOUR: ELECTROMAGNETIC WAVES AND SOILS. Chapter 10: Electromagnetism. Chapter 11: Electromagnetic Properties: Physical Description And Analytical Models. Chapter 12: Electromagnetic Properties: Data And Empirical Relations. Chapter 13: Laboratory Measurement Methods. PART FIVE: PROCESS MONITORING. Chapter 14: Process Monitoring With Elastic And Electromagnetic Waves. APPENDIX A: MATHEMATICAL CONCEPTS. REFERENCES.
448 citations
TL;DR: It is concluded that varicocelectomy reduces ROS levels and increases antioxidant activity of seminal plasma from infertile men with varicocele.
Abstract: Several theories have been advanced to explain the mechanisms by which varicocele impairs male fertility. These theories include scrotal hyperthermia, retrograde flow of adrenal or renal metabolites, Leydig cell dysfunction and hypoxia. Varicocele is reported to be associated with elevated reactive oxygen species (ROS) production in spermatozoa and diminished seminal plasma antioxidant activity. The aim of this study was to investigate whether surgical correction of varicocele might reduce ROS or increase the antioxidant capacity of seminal plasma from infertile patients with varicocele. The study group consisted of 68 infertile males, selected from patients scheduled for varicocelectomy at Cairo University Hospital during the year 1999. Seminal plasma levels of two ROS [malondialdehyde (MDA), hydrogen peroxide (H2O2)] and one ROS radical [nitric oxide (NO)] were estimated as well as six antioxidants [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), vitamin C (Vit C), vitamin E (Vit E), albumin) on the day prior to varicocelectomy. For comparison, the same parameters were measured again 3 and 6 months post-operatively. A statistically significant reduction in the 3 month post-operative levels of MDA, H2O2 and NO was observed when compared with the pre-operative values. A further significant reduction took place during the following 3 months. Four of the six antioxidants tested (SOD, CAT, GPx, and Vit C) showed a significant increase in seminal levels when comparing 3-month post-operative with pre-operative values. A further significant increase of the four antioxidant levels took place during the following 3 months. No significant change in the level of seminal plasma albumen took place during the first 3 months after varicocelectomy, however, a significant increase was noted during the next 3 months. In contrast to other antioxidants, seminal plasma levels of Vit E showed a significant decrease when comparing 3-month post-operative with pre-operative values. A further significant decrease took place during the following 3 months. It is concluded that varicocelectomy reduces ROS levels and increases antioxidant activity of seminal plasma from infertile men with varicocele.
204 citations
TL;DR: The results indicate that acute exposure to radiofrequency fields of commercially available cellular phones may modulate the oxidative stress of free radicals by enhancing lipid peroxidation and reducing the activation of SOD and GSH-Px, which are free radical scavengers.
187 citations
TL;DR: It is shown that AFLP is useful for estimating genetic relationships across a wide range of taxonomic levels, and for analyzing the evolutionary and historical development of cotton cultivars at the genomic level.
Abstract: Gossypium species (± 49) represent a vast resource of genetic diversity for the improvement of cultivated cotton. To determine intra- and inter-specific genetic relationships within a diverse collection of Gossypium taxa, we employed 16 AFLP primer combinations on three diploid species, Gossypium herbaceum L. (A1), Gossypium arboreum L. (A2) and Gossypium raimondii Ulbrich (D5), and 26 AD allotetraploid accessions (Gossypium barbadense L. and Gossypium hirsutum L.). A total of 1180 major AFLP bands were observed; 368 of these (31%) were polymorphic. Genetic similarities among all taxa ranged from 0.21 (between the diploid species G. arboreum and G. raimondii) up to 0.89 (within G. barbadense). Phenetic trees based on genetic similarities (UPGMA, N-J) were consistent with known taxonomic relationships. In some cases, well-supported phylogenetic relationships, as well as evidence of genetic reticulation, could also be inferred. UPGMA trees and principal coordinate analysis based on genetic similarity matrices were used to identify genetically distinct cultivars that are potentially important sources of germplasm for cotton improvement, particularly of fiber quality traits. We show that AFLP is useful for estimating genetic relationships across a wide range of taxonomic levels, and for analyzing the evolutionary and historical development of cotton cultivars at the genomic level.
175 citations
TL;DR: In this article, an update of intrauterine adhesions is presented. But they do not provide any details of the adhesion repair procedure, only the insertion procedure.
Abstract: (2001). Intrauterine adhesions: An update. Acta Obstetricia et Gynecologica Scandinavica: Vol. 80, No. 11, pp. 986-993.
155 citations
TL;DR: In this paper, the experimental determination of the maximum post-process annealing temperature for standard 035 /spl mu/m CMOS wafers with aluminum-based interconnections and tungsten plugs, without introducing significant modifications to their standard characteristics is reported.
Abstract: This paper reports on the experimental determination of the maximum post-process annealing temperature for standard 035 /spl mu/m CMOS wafers with aluminum based interconnections and tungsten plugs, without introducing significant modifications to their standard characteristics The impact of increasing the post-processing temperature from 475/spl deg/C to 575/spl deg/C, for periods varying between 30 and 90 min, on both the front and back end is analyzed 035 /spl mu/m CMOS technologies with different Al alloys, Al-1wt%Si-05wt%Cu (AlSiCu) or Al-05wt%Cu (AlCu), and different back end structures are considered It is illustrated that the maximum annealing temperature is a function of the structure and composition of the interconnection layers and their maximum allowable resistance increase It is also demonstrated that the transistor characteristics, the silicide quality and the leakage currents are as good as unaffected by annealing for 90 min at temperatures up to 525/spl deg/C
140 citations
TL;DR: Oscillation criteria for nth order differential equations with deviating arguments of the form x (n − 1) ( t ) α − 1 x ( n − 1), (t ) + F(t, x[g(t)]) = 0, n even are established in this paper.
132 citations
TL;DR: It is observed that VE is more effective than AA and garlic in restoring the inhibition of GST activity caused by CCl4 to the normal level after single dose treatments, and AA and VE are moreeffective than garlic in restore the induced TBARS level caused byCCl4to the normal control level after repeated dose treatments.
132 citations
TL;DR: In this paper, a polycrystalline aluminum sample with quasi-columnar grains, whose initial lattice orientations were mapped using the Orientation Imaging Microscopy (OIM) technique, was then compressed 40% along the axis of the columnar grains.
123 citations
TL;DR: Both HCV and hepatitis B virus infection increase the risk of HCC in Egyptian patients, whereas isolated Schistosoma infection does not.
Abstract: Background Egypt has one of the highest prevalence rates of hepatitis C virus (HCV) infection in the world; however, the risk and attribution related to HCV in Egyptian patients with hepatocellular carcinoma (HCC) remains unknown. Goals The current study was undertaken to estimate the risk of HCC in relation to HCV in Egypt. Study Thirty-three patients with HCC and 35 healthy controls who had a similar socioeconomic status were prospectively enrolled at the University of Cairo National Cancer Institute. Results Anti-HCV antibodies were present in 75.8% of the patients and in 42.9% of the controls (p = 0.01); hepatitis B surface antigen (HBsAg) was present in 15.2% of the patients and in 2.9% of the controls (p = 0.03). In addition, the sex-and age-adjusted odds ratio (OR) for anti-HCV antibodies was 5.1 (95% CI = 1.5-17.4) and for HBsAg was 13.2 (95% CI = 1.2-148.2). Concurrent Schistosoma mansoni and anti-HCV was associated with an OR of 10.3 (95% CI = 1.3-79.8), which was higher than that for anti-HCV (6.5; 95% CI = 1.6-26.6) and S. mansoni infection (0.2; 95% CI = 0.1-6.2) alone. Finally, we estimated the attributable fraction of HCC to HCV to be 64% in this study population and 48% in the general Egyptian population. Conclusions Both HCV and hepatitis B virus infection increase the risk of HCC in Egyptian patients, whereas isolated Schistosoma infection does not. Because of the very high prevalence rate of HCV in the general Egyptian population, it accounts for most HCC cases in Egypt.
121 citations
TL;DR: Tissue Cd was significantly increased after administration of either Cd doses and Al administration exhibited safer pattern than Cd, and Al concentration was shown to be increased in liver much more than in brain.
Abstract: This work aimed to study the relation- ship between the accumulation of cadmium (Cd) or aluminum (Al) in certain tissues and the levels of lipid peroxides as well as tissue antioxidants. To carry out such investigations, CdCl2 was given to rats in two dose levels; 0.5 or 2.0 mg=kg i.p for 1 day or daily repeated doses for 2 weeks. Al was given as AlCl3 either in a single dose of 100 mg/kg or daily repeated doses of 20 mg=kg for 2 and 4 weeks. The measured parameters were tissue malondialdehyde (MDA, index of lipid peroxidation) and reduced glutathione (GSH) levels as well as the activities of glutathione per- oxidase (GSH-PX), glutathione reductase (GSSG-R), and glucose-6-phosphate dehydrogenase (G-6-PDH) enzymes. Liver and kidney functions were assessed by measuring serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities as well as serum urea and creatinine concentrations. Cd and Al concentrations in the studied tissues were also measured. Results indicated that tissue Cd was sig- nificantly increased after administration of either Cd doses. After a single dose of 0.5 or 2.0 mg/kg CdCl2, the increase in tissue Cd levels were accompanied by an increase in MDA and a decrease in GSH levels. On the other hand, after repeated administration of Cd, tissue Cd accumulation was accompanied by increased hepatic and renal GSH levels with decrease in MDA content and a decrease in GSH-PX activity in liver. Liver function was affected at all dose regimens, whereas kidney function was affected only after 2 weeks administration of the higher dose. In Al treated rats, Al concentration was shown to be increased in liver much more than in brain. This was accompanied by a slight decrease in hepatic GSH level after 2 weeks and a decrease in GSH-PX activity after 4 weeks. Liver function was affected only after repeated injection of Al for 2 or 4 weeks. In general, Al administration exhibited safer pattern than Cd. C
TL;DR: The increased free radical generation during infections and LPS-induced stress suggests that brain oxidative status and energy is disturbed and vitamin E, beta-carotene and N-acetylcysteine are used to protect the brain from oxidative stress.
TL;DR: To map the gene responsible for AE, a genomewide screen was performed on 17 individuals, including 4 affected individuals, in a consanguineous Jordanian family, and all five affected individuals were found to be homozygous for a common haplotype.
Abstract: Acrodermatitis enteropathica (AE) is a rare autosomal recessive pediatric disease characterized by dermatitis, diarrhea, alopecia, and growth failure. The disease results from insufficient uptake of zinc by the intestine and can be fatal unless the diet is supplemented with zinc. To map the gene responsible for AE, a genomewide screen was performed on 17 individuals, including 4 affected individuals, in a consanguineous Jordanian family. Three markers—D8S373, D10S212, and D6S1021—had a pattern consistent with tight linkage to a recessive disease: one allele in the affected sibs and multiple alleles in unaffected sibs and parents. Two-point parametric linkage analysis using FASTLINK identified one region, D8S373, with a maximum LOD score >1.5 (1.94 at D8S373: recombination fraction .001). Twelve additional markers flanking D8S373 were used to genotype the extended family, to fine-map the AE gene. All five affected individuals—including one who was not genotyped in the genomewide screen—were found to be homozygous for a common haplotype, spanning ∼3.5 cM, defined by markers D8S1713 and D8S2334 on chromosomal region 8q24.3. To support these mapping data, seven consanguineous Egyptian families with eight patients with AE were genotyped using these markers, and six patients from five families were found to be homozygous in this region. Multipoint analysis with all consanguineous families, by Mapmaker/Homoz, resulted in a maximum LOD score of 3.89 between D8S1713 and D8S373. Sliding three-point analysis resulted in a maximum LOD score of 5.16 between markers D8S1727 and D8S1744.
TL;DR: ICSI carries a small but significant increased risk of abnormal karyotyping to the offspring and this risk appears to be equally distributed between autosomal and sex chromosome anomalies.
TL;DR: It is indicated that SOD may not reflect the level of peroxidation and points to the value of quercetin, CoQ10, and L-canavanine in ameliorating the oxidative status of brain during the early phase of endotoxic shock.
TL;DR: In this article, the static and dynamic characteristics of the hydrodynamic journal bearings lubricated with ferrofluid were investigated. And the critical speed at which whirling motion begins to occur was calculated.
TL;DR: It is concluded that repeated doses of antioxidants or garlic could reduce the toxic effects exerted by CCl(4) upon the liver, and probably other organs, through inhibition of cytochrome P450 system that activates CCl (4) into its active metabolite, trichloromethyl radical.
TL;DR: The technique of instrumental neutron activation analysis was applied as a sensitive nondestructive analytical tool for the determination of heavy metals and rare earth elements in phosphate fertilizer ingredients.
TL;DR: In this paper, a technique to restore the balance between freshwater and saline water in coastal aquifers in order to mitigate seawater intrusion problems is presented, where brackish water can be pumped from the dispersion zone and then used to develop green lands in coastal areas or to irrigate certain types of crops.
Abstract: This paper presents a technique to restore the balance between freshwater and saline water in coastal aquifers in order to mitigate seawater intrusion problems. Brackish water can be pumped from the dispersion zone and then used to develop green lands in the coastal areas or to irrigate certain types of crops. A two-dimensional finite element model (2D-FED), has been employed to verify this technique. The model is based on the dispersion zone approach with a variable density flow. Simulations were preformed in the vertical view and equiconcentration and equipotential lines were plotted for different locations of brackish water pumping. In all of the tested runs the width of dispersion zone has reduced significantly due to brackish water pumping. The quality of the pumped water differs according to the location of pumping. A study case on the Madras aquifer in India is presented.
TL;DR: A new pathway for the potential treatment of NSAID gastric ulceration through modulation of NO synthesis is created, regardless of the effect on gastric acidity.
TL;DR: In this article, the influence of S-quasinormally embedded subgroups of groups of prime power order on the structure of finite groups has been investigated and the results improve and extend recent results of Ballester-Bolinches and Pedraza-Aguilera (J. Pure Appl. Algebra 127 (1998) 113).
TL;DR: In this article, three-dimensional computations have been carried out on a typical single-phase power transformer using the Hopfield neural network energy minimization technique, as well as comparison with short circuit forces.
Abstract: Inrush currents are frequently encountered during the switching process of transformers. The purpose of this paper is to present an investigation of forces that appear as a result of inrush currents. While both short circuit and inrush transformer situations might seem identical, they vary significantly from the core magnetization viewpoint. Three-dimensional computations have been carried out on a typical single-phase power transformer using the Hopfield neural network energy minimization technique. Results are given in the paper as well as comparison with short circuit forces.
TL;DR: In this paper, a weakly nonlinear theory of wave propagation in superposed fluids in the presence of magnetic fields is presented, and the equations governing the evolution of the amplitude of the progressive as well as the standing waves are reported.
Abstract: In this paper a weakly nonlinear theory of wave propagation in superposed fluids in the presence of magnetic fields is presented. The equations governing the evolution of the amplitude of the progressive as well as the standing waves are reported. The nonlinear evolution of Rayleigh–Taylor instability (RTI) is examined in 2+1 dimensions in the context of Magnetohydrodynamics (MHD). This can be incorporated in studying the envelope properties of the 2+1 dimensional wave packet. We converted the resulting nonlinear equation (nonlinear Schrodinger (NLS) equation) for the evolution of the wave packets in 2+1 dimensions using the function transformation method into a sinh-Gordon equation and other nonlinear evolution equations. The latter depend only on one function ζ and we obtained several classes of general soliton solutions of these equations, leading to classes of soliton solutions of the 2+1 dimensional NLS equation. It contains some interesting specific solutions such as the N multiple solitons, the propagational breathers and the quadratic solitons, which contains the circular, elliptic and hyperbolic shape solitons. A stability analysis of these solutions is performed.
TL;DR: The results show that doxorubicin caused a statistically significant increase of 85%, 76% and 97% in plasma endothelin-1 at a cumulative dose levels of 10, 15 and 20 mg/kg, respectively, however, the level of plasma nitric oxide remained unchanged.
Abstract: The major limiting factor in long-term administration of doxorubicin is the development of cumulative dose-dependent cardiomyopathy and congestive heart failure. Although several mechanisms have been suggested to explain the exact cause of doxorubicin-induced cardiomyopathy, the role of the vascular endothelium-derived vasoactive mediators in the pathophysiology of this toxic effect is still unknown. Accordingly, the present study has been initiated to investigate whether the changes in plasma level of endothelin-1 and nitric oxide along with cardiac nitric oxide are associated with the development of doxorubicin-induced cardiomyopathy. Doxorubicin was injected with a single dose of 5 mg/kg and every other day with a dose of 5 mg/kg, intraperitoneally, to have four cumulative doses of, 10, 15, 20 and 25 mg/kg in five separate groups of male rats. An additional group receiving a single dose of 20 mg/kg and one receiving normal saline were also included in the study. Twenty-four hr after the last dose, the animals were sacrificed and the plasma levels of endothelin-1 and nitric oxide in addition to cardiac nitric oxide were determined. The results show that doxorubicin caused a statistically significant increase of 85%, 76% and 97% in plasma endothelin-1 at a cumulative dose levels of 10, 15 and 20 mg/kg, respectively. However, the level of plasma nitric oxide remained unchanged. Furthermore, doxorubicin treatment resulted in a significant dose-dependent increase in serum lactate dehydrogenase and creatine phosphokinase. In contrast, the increase in nitric oxide production in cardiac tissue by doxorubicin was not dose-dependent with the maximum increase (81%) at a cumulative dose of 10 mg/kg. It is worth mentioning that plasma endothelin-1 and cardiac nitric oxide were significantly increased at 24 hr after the single dose of 20 mg/kg doxorubicin. The increase of plasma endothelin-1 and cardiac nitric oxide with the cardiomyopathy enzymatic indices, may point to the conclusion that both endothelin-1 and cardiac nitric oxide are increased during the development of doxorubicin-induced cardiomyopathy.
TL;DR: The method is applicable for the assay of the four drugs under investigation in different dosage forms and the results are in good agreement with those obtained by the official method.
TL;DR: In this article, the authors investigated trends and periodicity of surface air temperature series from eight meteorological stations in the Eastern Mediterranean using various techniques, including Mann-Kendall rank test, low-pass filtering, autocorrelation spectral analysis and maximum entropy spectral analysis.
Abstract: Changes in surface air temperature during the last century are widely discussed among researchers in the field of climatic change. Using various techniques, we investigate trends and periodicity of surface air temperature series from eight meteorological stations in the Eastern Mediterranean. For the analysis, we use the Mann-Kendall rank test, low-pass filtering, autocorrelation spectral analysis and maximum entropy spectral analysis. The latter two tests are compared. The study is based on series over one hundred years in length for four stations, and over fifty years in length for the other four. Increasing and decreasing surface temperature trends were found. These trends, however, are only significant for Malta, Jerusalem, and Tripoli at the 99% confidence level (positive trend) and for Amman at the 95% confidence level (negative trend). We also found inter-decadal variations in surface air temperature, including a fairly regular quasi 20-year oscillation, although its amplitude varied between different cycles. A period of warming began around 1910 at all stations. During the 1970s, the annual mean temperature series exhibit warming, but this warming was not uniform, continuous or of the same order at all the stations. The results of the Autocorrelation Spectral Analysis and the Maximum Entropy Spectral Analysis are similar, pointing to the reliability of the results. The quasi-biennial oscillation (QBO) exists at all stations during both increasing and decreasing trends. Similarly, a broad maximum from 3–8 years (related to El Nino) is found at Malta, Athens, Jerusalem, Beirut, and Latakia. An inverse relationship between El Nino and the North Atlantic Oscillation with surface air temperature over the Eastern Mediterranean is found at a highly significant confidence level.
TL;DR: The PCR was more sensitive than the traditional cultural methods since it detected Brucella-DNA in 12 out of 120 semen samples while direct culture detected only 7 in the same semen samples, and the limit of detection by PCR was 100 CFU/ml of semen.
TL;DR: It is demonstrated that capsids have a phospholipase A2 activity thus far unknown to occur in viruses, which showed a substrate preference for phosphatidylethanolamine andosphatidylcholine over phosph atidylinositol.
Abstract: Bombyx mori densovirus (BmDNV-1), on the basis of the previously reported genome sequence, constitutes by itself a separate genus (Iteravirus) within the Densovirinae subfamily of parvoviruses. Inconsistencies in the genome organization, however, necessitated its reassessment. The genome sequence of new clones was determined and resulted in a completely different genome organization. The corrected sequence also contained conserved sequence motifs found in other parvoviruses. Some amino acids in the highly conserved domain in the unique region of VP1 were shared by critical amino acids in the catalytic site and Ca2+-binding loop of secreted phospholipase A2, such as from snake and bee venoms. Expression of this domain and determination of enzyme activity demonstrated that capsids have a phospholipase A2 activity thus far unknown to occur in viruses. This viral phospholipase A2, which is required shortly after entry into the cell, showed a substrate preference for phosphatidylethanolamine and phosphatidylcholine over phosphatidylinositol.
TL;DR: Patients with NIDDM and no symptoms of cardiovascular disease have a reduced LV systolic and diastolic function as compared with healthy subjects, and these abnormalities are correlated with the duration of diabetes and with other diabetic microangiopathies such as diabetic retinopathy and neuropathy.
Abstract: The aim of this study was to evaluate the relations between left ventricular (LV) functional abnormalities, microangiopathy, and autonomic dysfunction in patients with non-insulin-dependent diabetes mellitus (NIDDM). We studied 66 normotensive patients with NIDDM of > or =4 years' duration (age, 51 +/- 4.5 years; 35 men) and no clinical evidence of cardiac disease. Twenty-one healthy subjects matched for age and sex served as a control group. Echocardiography and Doppler studies were performed to assess LV systolic and diastolic function. Microangiopathy was assessed by fundus examination. Autonomic function was assessed by standing blood pressure and heart rate response to Valsalva maneuver. Patients with NIDDM had a lower ejection fraction (58% +/- 11% versus 66% +/- 4%, P <.0001), E-F deceleration slope (382 +/- 75 versus 427 +/- 31 cm/s(2), P <.05), and E velocity (55 +/- 11 vs. 58 +/- 6 cm/s, P =.02) of the mitral diastolic flow, compared with control subjects, respectively. Patients with ejection fraction <50% had a higher prevalence of retinopathy (65% versus 29%, P <.005), abnormal blood pressure response to standing (53% versus 8%, P <.0005), and proteinuria (65% versus 27%, P =.006). An inverse correlation was found between the duration of diabetes and both the ejection fraction (r = -0.53, P <.05) and E/A ratio (r = -0.4, P <.005). E/A ratio <1 was associated with a higher prevalence of retinopathy (49% versus 20%, P =.01) and abnormal blood pressure response to standing (29% versus 4%, P <.005). Patients with NIDDM and no symptoms of cardiovascular disease have a reduced LV systolic and diastolic function as compared with healthy subjects. LV systolic and diastolic abnormalities are correlated with the duration of diabetes and with other diabetic microangiopathies such as diabetic retinopathy and neuropathy.
TL;DR: The findings show that the molecular pathology of colorectal cancer in older as well as younger Egyptians has unique differences from Western patients, and schistosomiasis influences the molecular pathogenesis of some tumours.
Abstract: Colorectal carcinoma is uncommon in Egypt, but a high proportion of cases occurs before age 40 years and in the rectum. We compared the molecular pathology of 59 representative Egyptian patients aged 10-72 to Western patients with sporadic, young-onset, or hereditary non-polyposis colorectal cancer syndrome (HNPCC)-associated carcinoma and found significant differences. Most Egyptian cancers were rectal (51%) and poorly differentiated (58%). High levels of microsatellite instability (MSI-H) were frequent (37%) and attributable in some cases (36%) to methylation of the promoter of the hMLH1 mismatch repair gene, but no MSI-H cancer had loss of hMSH2 mismatch repair gene product of the type seen with germline hMSH2 mutation in HNPCC. K-ras mutation was uncommon (11%). In subset analyses, high frequencies of MSI-H in rectal carcinomas (36%) and p53 gene product overexpression in MSI-H cancers (50%) were found. MSI-H and K-ras mutation in Egyptians under age 40 were unusual (17% and 0%, respectively), and schistosomiasis was associated with MSI and K-ras mutation. Cluster analysis identified 2 groups: predominantly young men with poorly differentiated mucinous and signet-ring cell colorectal carcinoma lacking K-ras mutation; older patients who had well- or moderately differentiated adenocarcinoma often with MSI-H, K-ras mutation and schistosomiasis. Our findings show that the molecular pathology of colorectal cancer in older as well as younger Egyptians has unique differences from Western patients, and schistosomiasis influences the molecular pathogenesis of some tumours.