Show simple item record

dc.contributor.advisorAnderson, Diana
dc.contributor.advisorThorning, Paul
dc.contributor.authorOsman, Ilham F.
dc.date.accessioned2011-04-08T15:58:09Z
dc.date.available2011-04-08T15:58:09Z
dc.date.issued2011-04-08
dc.identifier.urihttp://hdl.handle.net/10454/4864
dc.description.abstractEver increasing applications of nanomaterials (materials with one or more dimension less than 100 nm) has raised awareness of their potential genotoxicity. They have unique physico¿chemical properties and so could have unpredictable effects. Zinc oxide (ZnO) and titanium dioxide (TiO2) are widely used in a number of commercial products. There are published studies indicating that some forms of these compounds may be photo-clastogenic in mammalian cells. What has not been investigated before is the effect of nanoparticles from these compounds in human germ cells. Thus the present study has examined their effects in the presence and absence of UV light in human sperm and compared responses to those obtained with human lymphocytes using the Comet assay to measure DNA damage. The effect of nanoparticles (40-70nm range) was studied in human sperm and lymphocytes in the dark, after pre-irradiation with UV and simultaneous irradiation with UV. The studies do provide some evidence that there are photo-genotoxic events in sperm and lymphocytes in the absence of overt toxicity. The cytotoxic and genotoxic potentials of ZnO and TiO2 as well as their effect on phosphotyrosine expression, were examined in the human epithelial cervical carcinoma cells (Hela cells). This was done to try and determine the underlying molecular events resulting from their exposure to ZnO and TiO2 nanoparticles occurring at the same time as DNA is damaged. Concentration- and time-dependent cytotoxicity, and an increase in DNA and cytogenetic damage with increasing nanoparticle concentrations were reported in this study. Mainly for zinc oxide, genotoxicity was clearly associated with an increase in tyrosine phosphorylation. Nanotechnology has raced ahead of nanotoxicology and little is known of the effects of nanoparticles in human systems, let alone in diseased individuals. Therefore, the effects of TiO2 nanoparticles in peripheral blood lymphocytes from patients with respiratory diseases (lung cancer, chronic obstructive pulmonary disease (COPD) and asthma) were compared with those in healthy individuals using genotoxic endpoints to determine whether there are any differences in sensitivity to nano-chemical insult between the patient and control groups. The results have shown concentration dependent genotoxic effects of TiO2 in both respiratory patient and control groups in the Comet assay and an increasing pattern of cytogenetic damage measured in the micronucleus assay without being statistically significant except when compared with the untreated controls of healthy individuals. Furthermore, modulation of ras p21 expression was investigated. Regardless of TiO2 treatment, only lung cancer and COPD patients expressed measurable ras p21 levels that showed modulation as the result of nanoparticle treatment. Results have suggested that both ZnO and TiO2 nanoparticles can be genotoxic over a range of concentrations without either photoa-ctivation or being cytotoxic.en_US
dc.language.isoenen_US
dc.rights© 2010 Osman, I. F. This work is licensed under a Creative Commons Attribution-Non-Commercial-Share-Alike License (http://creativecommons.org/licenses/by-nc-nd/2.0/uk).en_US
dc.subjectNanomaterialsen_US
dc.subjectHuman cellsen_US
dc.subjectRespiratory diseasesen_US
dc.subjectTiO2en_US
dc.subjectZnOen_US
dc.subjectSpermen_US
dc.subjectLymphocyteen_US
dc.subjectComet assayen_US
dc.subjectTyrosine phosphorylationen_US
dc.subjectMicronucleus assayen_US
dc.subjectLung canceren_US
dc.subjectCOPDen_US
dc.subjectAsthmaen_US
dc.subjectHealthy controlsen_US
dc.subjectRas oncoproteinen_US
dc.titleEffect of nanoparticles on human cells from healthy individuals and patients with respiratory diseases.en_US
dc.type.qualificationleveldoctoralen_US
dc.publisher.institutionUniversity of Bradfordeng
dc.publisher.departmentBiomedical Sciencesen_US
dc.typeThesiseng
dc.type.qualificationnamePhDen_US
dc.date.awarded2010
refterms.dateFOA2018-07-19T04:51:32Z


Item file(s)

Thumbnail
Name:
Ilham_Phd[1].pdf
Size:
4.179Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record