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Background: Despite the advancement in the fields of medical science and molecular biology, cancer is still the leading cause of death worldwide. Chemotherapy is a choice for treatment; however, the acquisition of chemoresistance is a major impediment for cancer management. Many mechanisms have been postulated regarding the acquisition of chemo-resistance in breast cancer and the impact on cellular signalling and the induction of apoptosis in tumour cells. The mechanism of the apoptotic mutation ofp53 and bcl-2 proteins is commonly associated with increased resistance to apoptosis and, therein, to chemotherapy. Objectives: The current study was aimed to investigate A172 and MDA-MB-231 cancer cells’sensitivity against chemotherapeutic drugs, including cisplatin, doxorubicin, and paclitaxel with different doses. Moreover, it estimates resistance of cancer cells by evaluating Nitric Oxide Synthase (NOS) expression and evaluate its correlation with the expression profile proteins of the apoptosis regulating Bcl-2 family. Methods: Dose-dependent sensitivity to cisplatin, doxorubicin or paclitaxel was evaluated on spheroid cultured A172 and MDA-MB-231 cells lines, was measured by time-lapse microscopy over a 72h period. Expressions of two Nitric Oxide (NO) synthases isoforms (iNOS, eNOS), anti-apoptotic (Bcl-2, phospho-Bcl-2, Mcl-1, and Bcl-xL) and proapoptotic (BID, Bim, Bok, Bad, Puma, and Bax) were evaluated by Western blot. The effect of NO modulation on antiand pro-apoptotic molecule expression was also studied using Western blot. Result: A172 cells show more resistance to chemotherapy drugs than MDA-MB-231 cancer cells, therefore, they need higher doses for apoptosis. Resistance of gliomas might be returned to higher significant expression of endothelial eNOS expression. It was clear that there is not a significant effect of NO modulation on the expression of pro- andantiapoptotic proteins on both cell lines. Conclusion: The present work provides a putative mechanism for the acquisition of drug resistance in breast cancer and glioma, which might be significant for clinical outcomes.

Microplastics (MPs), as a physical anthropogenic contaminant, represent a serious, human health concern due to their toxicity and ability to act as vectors for other pollutants and pathogens. This study aimed to screen for MP contamination in marine fish in Taif market, Saudi Arabia. A total of 22 fish species were used according to their different marine habitats and feedings. We have focused on extracting MPs from gills and muscles using KOH digestion. Nile red dye was used for the MP identification under fluorescence microscopy followed by the Fourier-transform infrared spectroscopy analysis. This study has reported MP contamination in gills and muscles of all the studied fish, in which poly(vinyl butyral) (PVB) was present in epipelagic species, poly(vinylidene fluoride) (PVDF) and poly(2,4,6,-tribromostyrene) (PtBS) were present in pelagic species, and PtBS and chlorosulfonated polyethylene were present in demersal/benthopelagic species. Moreover, benthic fish samples contain PtBS particles; reef-associated species have three different MP particles/fiber PtBS, PVDF, and poly(vinyl formal) and the rest of the studied species samples contain PtBS. The results highlight that the MP pollution increased to reach different species from the pelagic species to the benthic ones. PtBS as a type of polystyrene was the most dominant MP found in most species.

Taeniids, consisting of two genera Echinococcus and Taenia, are obligatory tapeworms of mammals, and their pathogenicity was due to infection with larval stages. Hydatid (the larval stage of Echinococcus granulosus) and coenurus (the larval stage of Taenia multiceps) cysts are prevalent in domestic, wild ruminants, livestock, swine, and dogs, and accidentally they could also be found in humans. They lead to different clinical manifestations that cause economic loss in livestock and human morbidity. In Saudi Arabia, few studies were performed on hydatid and coenurus cyst genetic variations. The main goal of the present study was to identify E. granulosus and T. multiceps cyst isolates collected from slaughtered Harri sheep in Saudi Arabia by partial sequencing with PCR amplification of the cytochrome C oxidase 1 (COX1) gene. Molecular and phylogenetic evaluation based on COX1 sequences indicated that cyst isolates belong to E. granulosus and T. multiceps, respectively, successfully submitted in NCBI Genbank. Molecular characterization showed a low nucleotide diversity with two submitted isolates of coenurus with related isolates of Genbank. Conversely, E. granulosus isolates showed higher nucleotide diversity. The reported data could serve as a foundation for future molecular epidemiological and biological studies.

Background: Nanoplastics (NPs) become one of the most threatening substances for living organisms in the aquatic and terrestrial environments. Due to their small size and high surface area, few studies have revealed their toxic impact on mainly marine organisms. However, there is scarcity on NPs impact on mammalian cells. Methods: We used 200-900 nm polyethylene nanoparticles (PE-NPs) to evaluate their cytotoxic and genotoxic effects on mammalian Vero E6 cell line using MTT and Comet assays. Result: Characterization of the selected PE-NPs confirmed their nano spherical shape, size and their low-density type. Serial dilution of PE-NPs decreases cell viability with 50% inhibition concentration (IC50) 91 μg/mL (at 24 h sampling time), 26 μg/mL (48 h) and 22 μg/mL (72 h) and an average IC50 = 46 μg/mL. Treatment of Vero E6 cells with the average IC50 significantly affects the genomic integrity by decrease of % DNA in head, increase of % DNA in tail, tail length (μm) and tail moment, in a time-dependent manner. Therefore, PE-NPs of the low-density type, that is widely used in different products including coatings and films, have cytotoxic and genotoxic effect on mammalian cells. NPs deserves more attention and further studies are needed to focus on their molecular mechanisms in vitro.

Seed priming is a novel approach that is undertaken to improve seed germination and therefore potentially enhance growth and yield. Low-cost, eco-friendly, and efficient seed treatment as a means of enhancing growth and yield is still being sought for high-value crops such as pomegranates (Punica granatum L.), particularly in areas situated at high altitudes such as the Taif region. The uptake of nanoparticles (NPs) by plants provides a potential pathway for NP exposure. Therefore, it is imperative to understand NP uptake via seed priming and their unique properties within plants. In the present study, titanium dioxide nanoparticles (TiO2NPs) were green-synthesized and utilized as priming agents for pomegranate seeds at a concentration of 40 mg/mL for 24 h. The adsorption of NPs was verified by scanning electron microscopy (SEM) and energy dispersive X-ray analysis/spectroscopy (EDX), while their incorporation was detected by transmission electron microscopy (TEM). To validate the EM results, X-ray fluorescence (XRF) and inductively coupled plasma optical emission spectroscopy (ICP–OES) techniques were further undertaken. The results confirmed the successful synthesis of pure anatase TiO2NPs by employing aqueous extracts of pomegranate fruit peel (PPE) and coffee ground beans (CE). All of the analytical techniques employed in this research confirmed the incorporation of TiO2NPs inside seeds, even after storage during priming treatment. This study lays the foundation for future sustainable seed technologies in terms of crop productivity and seed germination.

The low price and high contents of bioactive compounds in citrus peel increase interest in using it in various applications. Mandarin (Citrus reticluata) peel belongs to Rutaceae family and is rich with antioxidants. However, limited studies are available on toxicity of Mandarin peel oil (MPO) on human Prostate Cancer (PC3) cells. Therefore, the present study was conducted to study the cytotoxicity and genotoxicity of MPO on Human normal Fibroblast (HFB4) and PC3 cell lines. The half maximal inhibitory (IC50) and safe concentration of MPO was detected using MTT assay. Comet and DNA fragmentation assays were performed to assess apoptotic DNA damage. Also, the ROS level was evaluated and the mRNA expression level of apoptotic and antiapoptotic genes were measured using RT-PCR. Results of the cytotoxic test showed that MPO induced preferential inhibition of PC3 cells proliferation in a concentration-dependent manner with IC50 10.97 µg/ml. The time-dependent induction of DNA breaks demonstrated in PC3 cells treated with MPO safe concentration-stimulated ROS generation and apoptotic DNA damage through increased expression of tumor suppressor p53 and Bax genes and decreased expression of Bcl2 and MDM2 genes. In contrast, non-significant changes were observed in the DNA integrity, ROS levels and expressions of the tested genes in the normal HFB4 cells treated with MPO. Thus, we concluded that MPO induced preferential cytotoxic and genotoxic effects toward cancerous PC3 with no noticeable toxic effects in normal HFB4 cells and therefore further in vivo studies are recommended to test its possible use as anticancer drugs.

Nano-fertilizers are innovative materials created by nanotechnology methodologies that may potentially replace traditional fertilizers due to their rapid absorption and controlled distribution of nutrients in plants. In the current study, phosphorous-containing hydroxyapatite nanoparticles (nHAP) were synthesized as a novel phosphorus nano-fertilizer using an environmentally friendly green synthesis approach using pomegranate peel (PPE) and coffee ground (CE) extracts. nHAPs were physicochemically characterized and biologically evaluated utilizing the analysis of biochemical parameters such as photosynthetic activity, carbohydrate levels, metabolites, and biocompatibility changes in Punica granatum L. Cytocompatibility with mammalian cells was also investigated based on MTT assay on a Vero cell line. Dynamic light scattering (DLS) and zeta potential analysis were used to characterize the nHAPs for size and surface charge as well as morphology using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nHAPs were found to have different shapes with average sizes of 229.6 nm, 120.6 nm (nHAPs_PPE) and 167.5 nm, 153 nm (nHAPs_CE) using DLS and TEM, respectively. Overall, the present results showed that the synthesized nHAPs had a negative impact on the selected biochemical, cytotoxic, and genotoxic parameters, indicating that the evaluation of nHAP synthesized by this approach has a wide range of applications, especially as a nano-fertilizer.

Cancer was ranked as the second leading cause of death, and colon cancer has been reported as the third most frequent cancer worldwide. Chemotherapeutic drugs act on normal and cancerous cells similarly; therefore, they have various adverse side effects. Nanoparticles were identified to have a controlled effect on different cancer cell lines. The present study is aimed at studying biosynthesis silver nanoparticles by using aqueous Olea chrysophylla and Lavandula dentata leaf extracts, separately, and evaluating their anticancer potential. Silver nanoparticles were characterized by using SEM, XRD, FTIR, zeta potential, and size distribution mean, and their antiproliferative and apoptotic potentials were evaluated on HCT116 cells. Results show the formation of silver nanoparticles Olea-AgNPs and Lav-AgNPs due to the change of color to dark brown, and characterization revealed their crystalline shape with a mean size of 284.5 nm for Lav-AgNPs and 328.6 nm for Olea-AgNPs. Lav-AgNPs shows more stability than Olea-AgNPs due to its higher negative zeta potential (-14.3 mV) than nanoparticles biosynthesized from Olea leaves (-0.877 mV). Conversely, Lav-AgNPs shows more effective antiproliferative potential on HCT116 with (IC50 = 59.79 μg/ml) than Olea-AgNPs (IC50 = 99.35 μg/ml). However, Olea-AgNPs significantly increased the late stage of apoptotic and necrotic cells in comparison to Lav-AgNPs-treated cells in flow cytometry assay. Silver nanoparticles biosynthesized from Olea and lavender show anticancer potential with a more effective potential reported compared to Lav-AgNPs.

Taeniids, consisting of two genera Echinococcus and Taenia, are obligatory tapeworms of mammals, and their pathogenicity was due to infection with larval stages. Hydatid (the larval stage of Echinococcus granulosus) and coenurus (the larval stage of Taenia multiceps) cysts are prevalent in domestic, wild ruminants, livestock, swine, and dogs, and accidentally they could also be found in humans. They lead to different clinical manifestations that cause economic loss in livestock and human morbidity. In Saudi Arabia, few studies were performed on hydatid and coenurus cyst genetic variations. The main goal of the present study was to identify E. granulosus and T. multiceps cyst isolates collected from slaughtered Harri sheep in Saudi Arabia by partial sequencing with PCR amplification of the cytochrome C oxidase 1 (COX1) gene. Molecular and phylogenetic evaluation based on COX1 sequences indicated that cyst isolates belong to E. granulosus and T. multiceps, respectively, successfully submitted in NCBI Genbank. Molecular characterization showed a low nucleotide diversity with two submitted isolates of coenurus with related isolates of Genbank. Conversely, E. granulosus isolates showed higher nucleotide diversity. The reported data could serve as a foundation for future molecular epidemiological and biological studies.

Green synthesis of silver nanoparticles (AgNPs) represents one of the most economical, simple, and eco-friendly method other than chemically based synthesis. Many studies used various plant extracts for AgNPs synthesis to evaluate their anticancer or cytotoxic potentials. Taif governate is a high-altitude region of Saudi Arabia with a great diversity of plants with different medicinal value. In the present study Olea chrysophylla and Lavandula dentata L. leaves extracts were used for biological synthesis of AgNPs, while trisodium citrate was used for chemical synthesis. Characterization of synthesized silver nanoparticles was done using zeta potential, average size distribution, SEM, XRD, and FTIR techniques. Cytotoxicity assay was done to evaluate their effect on normal human gingival fibroblast GF01 cells. We have succeeded in biological and chemical synthesis of AgNPs that was determined by color change, with crystalline shape that confirmed by SEM and XRD. FTIR confirms the functional groups that are responsible for AgNPs capping and stabilization due to their synthesis. It was reported that Chem-AgNPs (62.62nm) has the smallest size due to its highest negativity (-50 mV) then Lav-AgNPs (284.5 nm), and Olea-AgNPs (328.6 nm). In addition, Chem-AgNPs shows the least toxicity on normal GF01 cells with concentrations (IC50= 489.73μg/ml), then Olea AgNPs (IC50= 186.51μg/ml), while Lav-AgNPs (IC50= 44.95μg/ml) shows the greatest toxicity on normal cells. In conclusion, surprisingly, Chem-AgNPs shows lower cytotoxic effect with its smaller size than biologically synthesized AgNPs due to trisodium citrate reduction effect that gives a good challenge for AgNPs safe chemical synthesis.

Background Toxoplasmosis resulting from infection with the Toxoplasma parasite has become an endemic disease worldwide. Recently, a few studies have reported a high prevalence of Toxoplasmosis infections among Saudi Arabian women. This disease could become life threatening for pregnant women and for immunodeficient people. There is evidence that infections during pregnancy, especially in the early stages, are associated with neurodevelopmental disorders. Autism disorder represents one of the most common neurodevelopmental disorders worldwide; it is associated with delayed language development, weak communication interaction, and repetitive behavior. The relationship between prenatal toxoplasmosis and autism in childhood remains unclear. The present study aims to report a link between maternal toxoplasmosis and autistic offspring among Saudi Arabian women. Method Blood samples (36 maternal, 36 from their non-autistic children, and 36 from their autistic children) were collected for serological and molecular evaluation. Results A toxoplasmosis infection was reported for 33.34% of participants using an ELISA assay (5.56% IgG+/IgM+, 11.11% IgG−/IgM+, and 16.67% IgG+/IgM-); however, a nested PCR assay targeting B1 toxoplasmosis specific genes recorded positive tests for 80.56% of the samples. In addition, the present study detected several points of mutation of mtDNA including NADH dehydrogenase (ND1, ND4) and Cyt B genes and the nDNA pyruvate kinase (PK) gene for autistic children infected with toxoplasmosis. Conclusion Considering previous assumptions, we suggest that a maternal toxoplasmosis infection could have a role in the development of childhood autism linked to mtDNA and nDNA impairment.

Silver nanoparticles (AgNPs) were extensively used in different fields worldwide. There is a continued increase in their productions to fulfill various uses. Biological and chemical AgNP syntheses were the most popular mechanisms in this field. Agrowastes are rich in proteins, phenolics, and flavonoids that could act as bioreductant agents in AgNP biological synthesis. The present study was aimed at synthesizing AgNPs via chemical and biological methods using trisodium citrate, pomegranate fruit peel, and coffee ground waste extracts. Moreover, silver nanoparticles were monitored by UV-vis spectroscopy and characterized using zeta potential, size distribution mean, scanning electron microscope (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectroscopy (FTIR). Four pathogenic bacterial strains (Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, and MRSA) were used to assess the antimicrobial effect of the synthesized AgNPs (2, 4, and 8 mg/ml). Results report the successful formation of silver nanoparticles chemically (AgNPs_Chem) and biologically by using pomegranate peel extract (AgNPs_PPE) and coffee ground waste extract (AgNPs_CE) due to the change of color to dark brown that is confirmed by UV-vis sharp absorption spectra at specific wavelengths. Characterization using SEM and XRD revealed their crystalline shape with a mean size of AgNPs _ Chem = 62.75 , AgNPs _ CE = 273.7 nm , and AgNPs _ PPE = 591.9 nm . AgNPs_Chem show higher negativity of zeta potential (−46.7 mV) than AgNPs_CE (−12.6 mV), followed by AgNPs_PPE (−7.98 mV), which had the least stability. All the synthesized AgNPs show antimicrobial potential on all selected strains. However, 8 mg/ml shows the most effective concentration and has more efficiency on K. pneumoniae than others. Overall, the results highlight that the use of agrowastes could be an ecofriendly way to synthesize AgNPs biologically that have the same antimicrobial effect as the chemically synthesized AgNPs.

Worldwide, thalassemia represents one of the most common genetic disorders. There is a prevalence of Beta-thalassemia in Kingdom of Saudi Arabia (KSA), however there is a genetic counseling availability and an existence of mandatory premarital testing policy. Few studies detect molecular mutations of thalassemia genes in different KSA governates, including Makkah, Hufuf, Qatif, and Dammam but in our peer knowledge there is no reports on high altitude Taif region. The aim of the present study is to evaluate the molecular mutation analysis of β-thalassemia gene in El Taif province (as a high-altitude area) patients of KSA and to estimate the iron overload toxicity due to thalassemia syndrome on the hotspot noncoding D-loop region (hypervariable, HV2 gene fragment) of mtDNA. Blood samples were collected from total 25 β-thalassemia patients and 25 normal control that were used for HPLC, hematological analysis and different molecular evaluations. Extracted nuclear DNA from blood sample was used to detect known mutations accompanied with β-thalassemia in other countries using PCR-ARMS technique targeting IVSII-1, IVSI-5, Codon 8/9, Cd44 and Cd5 genes’ mutations. Moreover, mtDNA was used to detect point of mutation of HV2 fragment in the D-loop region using PCR-SSCP and then sequencing. Results show significant increase in the level of HbA2 and decrease of HbA in comparison to control by using HPLC. PCR-ARMS reports that all β-thalassemia patients have heterozygous alleles of wild and mutated regions with nucleotide transition/transversion of IVSI-5 (AC>AG), Codon 8/9 (CT>CC), and Cd44 (GG>GA), however no point of mutation was detected in IVSII-1 (AC>AT) Cd5 (CT>CG) genes. Moreover, PCR-SSCP shows points of mutations for β-thalassemia HV2 fragment that were confirmed by sequencing in the form of base pairs deletion, insertion and transition/transversion. For the first time, the present study reports the presence of 2 bps found in HV2 region that might be specific to KSA nations and not found in other countries. In conclusion, our results were in concurrent with other studies in the presence of specific genetic mutations in β-thalassemia patients that is accompanied with points of mutations in HV2 region of high altitude Taif governate.

Increased human exposure to cobalt oxide nanoparticles (CoO-NPs) because of their widespread use in many industrial and medical applications makes the study of genotoxicity and mutagenicity necessa...

The present paper deals with the of Rayleigh surface waves in fiber-reinforced solid anisotropic magneto-thermo-viscoelastic media, a pre-stressed elastic layer of finite thickness over a h...

Lepidium sativum (LS) is an annual fast-growing herb that is now cultivated worldwide. It has been used for a long time as a traditional way in curing various diseases due to its different pharmacological properties. However, excess use of alternative medicine without medical supervision could lead to reverse toxic effect. Therefore, the present study aimed to evaluate the cytotoxic, genotoxic and mutagenic effect of oral administration of excess LS seeds aqueous extract in vivo. Animals were segregated into six groups; negative control, LS (200mg/kg), LS (400mg/kg), and LS (800mg/kg) daily administration for two consecutive weeks and LS (200mg/kg), and LS (400mg/kg) day by day administration for three consecutive weeks. Results show that high doses of LS, especially for daily schedule, increases mortality rate, leads to animal weakness, hair loss and abdominal bloating. In addition, LS administration distorts colon, liver, kidney and testis tissue in a dose dependent manner. Also, daily treatment increases cytotoxicity and genotoxicity of bone marrow cells detected by micronucleus assay and increases sperm abnormalities. Surprisingly, the present study records point of mutation in exon 5 of P53 gene in colon and liver tissue using SSCP assay. In conclusion, LS seeds extract is toxic in high dose administration for daily treatment and should be used in a therapeutic dose with no excess under medical supervision.

This paper is concerned with giving a mathematical model on the propagation of Rayleigh waves in a homogeneous magneto-thermo-viscoelastic, pre-stressed elastic half – space subjected to theinitial stress and rotation. The dispersion equation has been derived for a half-space, when both media are considered as pre-stressed and the effect of rotation and initial stressshown in earlier investigators.Numerical results have been obtained in the physical domain. Numerical simulated results are depicted graphically to show the effect of rotation and magnetic field and initial stress on Rayleigh wave velocity. Comparison was made with the results obtained in the presence and absence of the rotation , initial stressand magnetic field. The study shows that there is a variational effect of magneto-elasticityand rotation, initial stress on the Rayleigh wave velocity.

The present paper is aimed at studying the effects of thermal relaxation time and gravity of a two-dimensional problem with anisotropic semi-infinite solid media with the deformation of fiber-reinforced generalized thermoplastic. The harmonic function techniques are used. The thermal stresses, temperature and displacement have been obtained. These expressions are calculated numerically for two values of elastic constants for mediums M1 and M2 respectively. The results obtained are displayed by graphs to clear the phenomena physical meaning. The results indicate that the effect of gravity, relaxation times and parameters of fibre-reinforced of the material medium are very pronounced.

Ribavirin (1-β- d -ribofuranosyl-1,2,4-triazole-3-carboxamide) is a widely used broad-spectrum antiviral drug. Recently, several reports revealed genotoxic effects of ribavirin in vivo and in vitro , which were correlated with the production of reactive oxygen species (ROS). This study aimed to evaluate the genotoxicity of ribavirin and to investigate the role of the natural antioxidant silymarin to modulate this genotoxicity. Male albino mice (age, 8–10 weeks) were injected intraperitoneally (i.p.) with ribavirin at three dose levels (20, 75 and 130 mg/kg bw) either in a single injection (acute treatment) or in multiple injections on five consecutive days (sub-acute treatment). Other comparable groups were treated with silymarin (70 mg/kg bw) 1 h before the injection with ribavirin. Mice were sacrificed at different sampling times (24, 48 and 72 h) after the last ribavirin treatment. Micronucleus (MN) and single-strand conformation polymorphism (SSCP) assays were used to assess genotoxic and cytotoxic effects of ribavirin and to evaluate the protective effect of the pre-treatment with silymarin. Our results reveal genotoxic and cytotoxic effects of ribavirin in the MN assay. Pre-treatment with silymarin reduced the toxicity of ribavirin. In the SSCP assay, ribavirin treatment did not induce any mutations in the two selected sites in the D-loop of mitochondrial DNA (mtDNA).

Objective: Cobalt nanoparticles (NPs), especially cobalt oxide NPs (Co3O4 NPs) are attracting unique shaped NPs that are used in different biomedical applications and medicine. Different in vitro studies report their toxic and carcinogenic effect but limited in vivo studies were present on its genotoxic potential. The present study was aimed to evaluate the genotoxic potential of Co3O4 NPs on bone marrow cells and sperms and the protective role of omega-3 in male albino mice. Methods: Animals were segregated into four groups that were orally treated for 3 consecutive days, Group 1: Negative control; Group 2: Omega-3 (250 mg/kg); Group 3: Co3O4 NPs (20 mg/kg); and Group 4: Combined group (250 mg/kg Omega-3 and Co3O4 NPs 20 mg/kg). Results: The present results show that Co3O4 NPs administration significantly increased number of micronucleated polychromatic erythrocytes (PCEs)/1000 PCEs, sperm abnormalities, and DNA damage, significantly decreased sperm motility and concentration in comparison to negative control group. However, Omega-3 administration in the combined group modulates the genotoxic potential of Co3O4 NPs in comparison to Co3O4 NPs group. Conclusion: The present study reports the genotoxic potential of Co3O4 NPs in vivo and assesses the protective role of Omega-3 administration due to its antioxidant effect.

Titanium dioxide nanoparticles (TiO2NPs) are excessively used and represent one of the top five most commonly used nanoparticles worldwide. Recently, various studies referred to their toxic potential on various organs using different treatment route. Male Swiss Webster mice were orally administrated TiO2NPs (500 mg/kg b.w.) daily for five consecutive days and then animals were sacrificed at 24 h, 7 days, or 14 days after the last treatment. The present results report that exposure to TiO2NPs produces mild to moderate changes in the cytoarchitecture of brain tissue in a time dependent manner. Moreover, Comet assay revealed the apoptotic DNA fragmentation, while PCR-SSCP pattern and direct sequencing showed point mutation of Presenilin 1 gene at exon 5, gene linked to inherited forms of the Alzheimer’s disease. Therefore, from these findings, the present study concluded that TiO2NPs is genotoxic and mutagenic to brain tissue which in turn might lead to Alzheimer’s disease incidence.

p53 gene is one of the most frequently mutated genes found in the human colonic tumors. Mice have been used as an experimental model to study the pathogenesis of colon cancer in humans. The alterations in cancer genes and proteins found in the mouse large intestinal tumors included mutations which are hallmarks of human colon cancer, probably contributed to the pathogenesis of the large intestinal carcinomas in mice following o-nitrotoluene (o-nt) exposure. Aim of Study: Detection of p53 gene mutations in colon precancerous stage. Materials and Methods: In this study, mice colon precancerous stage induced by o-nt were examined for the presence of point mutations in highly conserved coding region (exons 5-8) and outside it (exons 10, 11) using a single-strand conformation polymorphism assay (SSCP). Results: SSCP analysis showed no differences in banding patterns between the normal negative control group and o-nt-induced precancerous stage in mice colon. Conclusion: The results from the present study indicate that point mutations in the p53 gene, in the coding region (exons 5-8) and outside it (exons 10, 11), are not involved in the development of the colon precancerous stage induced by o-nt in mice.