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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An in vitro investigation into the protective and genotoxic effects of myricetin bulk and nano forms in lymphocytes of MGUS patients and healthy individuals

Akhtar, Shabana, Najafzadeh, Mojgan, Isreb, Mohammad, Newton, L., Gopalan, Rajendran C., Anderson, Diana 15 June 2020 (has links)
Yes / The present study investigated the genoprotective and genotoxic effects of myricetin bulk (10 μM) and nano forms (20 μM) in the lymphocytes from pre-cancerous, monoclonal gammopathy of unknown significance (MGUS) patients and healthy individuals using the Comet and micronucleus assays. The study also evaluated the effect of myricetin on P53 expression levels, using the Western blot technique. Results showed that throughout the in-vitro treatment, lymphocytes from the patients group had higher levels of baseline DNA damage compared to the healthy group. Myricetin in both forms induced significant DNA damage, only at higher concentrations (>40 μM). The micronucleus assay showed a significant reduction (P < 0.01) in the frequency of micronuclei in mono-nucleated cells in the patient group treated with the nano form of myricetin at the non-toxic dose of 20 μM. There was a significant increase in both gene and protein P53 levels in lymphocytes isolated from healthy individuals and pre-cancerous patients. These results suggested a protective effect of myricetin and indicated its nutritional supplement potential for protection against cancer development among patients suffering from MGUS. / This study was kindly funded by Mr Nasir Qayyum, Bradford, UK.
2

DESENVOLVIMENTO DE UM MÉTODO DE ANÁLISE IN VITRO DA CAPACIDADE GENOMODIFICADORA DE COMPOSTOS QUÍMICOS E SINTÉTICOS / DEVELOPMENT OF A METHOD FOR IN VITRO ANALYSIS OF GENOMODIFIER CAPACITY OF CHEMICALS AND SYNTHETIC

Cadoná, Francine Carla 16 July 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / DNA is a molecule susceptible to the attack of many toxic substances. So, studies on the toxic effects of chemical are very important. Tests that evaluate substances genomodifier (presenting action genoprotetora or genotoxic), how the Comet Assay, are often complex and laborious. Therefore an ultrasensitive and fast protocol no-cell is presented for the quantification DNA triggered by chemical compounds, called GEMO Assay (Genomodifier capacity assay). This assay includes a prooxidant standardized (H2O2, 3M) that is used to compare the effects on dsDNA damage of the compound-test that is evaluated with and without addition this prooxidant. The assay is performed in black 96-well plate and use Quant-iT PicoGreen® dsDNA Reagent and DNA from Calf Thymus. The vitamin C was used like compound-test in different concentrations (0.1, 0.3, 1, 3 and 10 μg/mL). For validation of GEMO Assay was used PBMCs (peripheral blood mononuclear cells) and HT29 (colon carcinoma cell line) exposed the same conditions that the proposed test and evaluated at different tests already well described in the literature: Alkaline Comet Assay, MTT, DCFH-DA and TBARS. The results showed high correlation with GEMO Assay, confirming the validation. Then the test developed in this work offers high sensitivity for detecting genomodifier substances without interference if biological systems. / Pelo fato do DNA ser uma molécula suscetível ao ataque muitas de substâncias, estudos sobre efeitos tóxicos ou fitoterapêuticos de compostos químicos são necessários. Muitos ensaios que analisam o efeito genomodificador de substâncias, às vezes, são relativamente complexos, como o Teste do Cometa. Entende-se por ação genomodificadora aquela em que a substância testada ou apresenta genoproteção ou genotoxicidade. Baseado na existência de ensaios in vitro que servem como triagem para avaliar a capacidade antioxidante de um dado composto, como o DPPH, o objetivo deste estudo foi desenvolver e validar um método in vitro da capacidade genomodificadora de compostos químicos e sintéticos. Assim, um ultrassensível e rápido protocolo que não utiliza sistemas biológicos foi desenvolvido para a quantificação do DNA dupla-fita (dsDNA) exposto a substâncias químicas, denominado de Teste GEMO (Teste de Capacidade Genomodificadora). Esse método foi concebido para placa preta de 96 poços, utilizando um corante altamente específico de dsDNA (PicoGreen®) e DNA purificado de timo de bezerro (dsDNA). O teste inclui um pró-oxidante de referência, peróxido de hidrogênio (H2O2 3M), que permite a análise comparativa dos dados obtidos, classificando a substância testada em vários níveis de genotoxicidade e ainda se a mesma apresenta potencial de genoproteção. Para o desenvolvimento do teste foi utilizado um antioxidante bem conhecido pelo seu papel genoprotetor e antitumoral, a vitamina C em diferentes concentrações (0.1, 0.3, 1, 3 e 10 μg/mL). Para a validação do Teste GEMO, foram utilizadas células mononucleares de sangue periférico (PBMCs) e células de adenocarcinoma colorretal (HT29), expostas as mesmas condições que o teste proposto e submetidas a diferentes testes já bem descritos na literatura: Teste do Cometa Alcalino, MTT, DCFH-DA e TBARS. Os resultados mostraram alta correlação com Teste GEMO, confirmando a validação. Portanto, o ensaio desenvolvido nesse trabalho oferece alta sensibilidade para detectar compostos genomodificadores, sem a interferência de sistemas biológicos.
3

Molecular mechanisms of myricetin bulk and nano forms mediating genoprotective and genotoxic effects in lymphocytes from pre-cancerous and myeloma patients

Akhtar, Shabana January 2018 (has links)
Cancer is one of the leading causes of death across the globe which needs appropriate and cost-effective treatment. Several recent studies have suggested that dietary intake of various flavonoids such as myricetin have a protective effect against different types of cancers and cardiovascular diseases. The present study was conducted to investigate the genoprotective and genotoxic effects of myricetin nano and bulk forms on the lymphocytes from pre-cancerous and multiple myeloma cancer patients compared to those from healthy individuals. Also, to investigate the protective potential of myricetin bulk and nano against the oxidative stress produced in vitro by 2- amino-1-methyl-6 phenylimidazo [4, 5-b] pyridine and reactive oxygen species- induced DNA damage using the Comet assay, micronucleus assay, cellular reactive oxygen species and glutathione detection assay, Western blotting, real-time polymerase chain reaction and immunofluorescence. Lymphocytes from the patient groups showed significantly higher levels of basal DNA damage compared to the lymphocytes from healthy individuals which was observed throughout the in vitro treatment. Myricetin in both forms has not induced any significant DNA damage in all of the investigative groups at selective lower concentrations; in fact, the results demonstrate a reduction in DNA damage upon treating with myricetin nano in lymphocytes from pre-cancerous patients demonstrated by significant reduction in micronuclei formation in mononucleated cells. DNA repair capacity of myricetin bulk and nano was determined by co-treating the drugs with hydrogen peroxide. Myricetin significantly reduced the oxidative stress related damage caused by hydrogen peroxide, where myricetin nano seemed to be more effective employing the Comet assay. In the presence of myricetin bulk and nano, the damaging effects of 2- amino-1-methyl-6 phenylimidazo [4,5-b] pyridine were considerably decreased, where myricetin nano was more effective. This could be because nanoparticles have a larger surface area which could improve their reactivity and also the reduction in size of the particles could improve the anti-cancer properties of this compound. Myricetin has shown genoprotective and anti-oxidant effects by demonstrating the potential to reduce DNA damage caused by over-production of reactive oxygen species and oxidative stress. It has also shown anti-cancer potential in the lymphocytes from multiple myeloma patients by regulating the apoptosis related proteins, dependent on oxidative stress. Therefore, this study suggests that myricetin supplementation in our regular diet with enhanced bioavailability could have potential health beneficial effects and possibly protect against various diseases including cancer.
4

Applying a new technique, the interferon gamma liposomal delivery system to improve drug delivery in the treatment of Lung Cancer

Alhawamdeh, Maysa F.J. January 2021 (has links)
Lung cancer is one of the main causes of death worldwide, with most patients suffering from an advanced unresectable or metastatic non-small cell lung cancer. The mortality trends are mostly related to patterns of tobacco use, specifically from cigarettes. Tobacco is the basic etiological agent found as a consequence of the inhalation of tobacco smoke. Published data show the use of interferons (IFNs) in the treatment of lung tumours due to their potential in displaying antiproliferative, anti-angiogenic, immunoregulatory, and proapoptotic effects. Type1 IFNs have been employed as treatments for many types of cancer, both for haematological cancers and solid tumours. The IFN-γ (naked) functions as an anticancer agent against various forms of cancer. Hence, this study aimed to investigate the genoprotective and genotoxic effects of IFN-γ liposome (nano) on 42 blood samples from lung cancer patients, compared to the same sample size from healthy individuals. The effectiveness of IFN- γ liposome against oxidative stress was also evaluated in this study. A concentration of 100U/ml of IFN-γ liposome was used to treat the lymphocytes in: Comet and micronucleus assays, Comet repair, Western blotting and real-time polymerase chain reaction (qPCR) were based on a preliminary test for the optimal dose. The lymphocytes from lung cancer patients presented with higher DNA damage levels than those of healthy individuals. IFN-γ liposome was not found to induce any DNA damage in the lymphocytes. Also, it caused a significant reduction in DNA damage in the lymphocytes from lung cancer patients in; Comet, Comet repair and micronucleus assays. Furthermore, the 100U/ml of IFN-γ liposome significantly reduced the oxidative stress caused by H2O2 and appeared to be effective in both groups using the Comet and micronucleus assays. Results from; Comet, Comet repair and micronucleus assays were consistent. The data obtained indicated that IFN-γ in both forms (naked INF-γ and INF-γ nano-liposome) may potentially be effective for the treatment of lung cancer and showed the ability of IFN-γ liposome to reduce the DNA damage more than the naked form. The IFN-γ in both forms has also shown anti-cancer potential in the lymphocytes from lung cancer patients by regulating the expression of p53, p21, Bcl-2 at mRNA and protein levels by up-regulating the p53 and p21 to mediate cell cycle arrest and DNA repair in lung cancer patients. The findings of this study are consistent with the view that the naked IFN-γ and liposome could have a significant role in cancer treatment, including lung cancer. / Mutah University in Jordan
5

AVALIAÇÃO DA ATIVIDADE PROTETORA DO GUARANÁ (Paullinia cupana var. sorbilis) EM MODELO DE HEPATOXICIDADE INDUZIDA POR TETRACLORETO DE CARBONO EM RATOS / ASSESSMENT OF HEPATOPROTECTIVE EFFECT OF GUARANÁ (PAULLINIA CUPANA VAR. SORBILIS) IN CCL4- INDUCED TOXICITY IN RATS

Kober, Helena 12 July 2013 (has links)
The liver diseases represent a relevant health problem, affecting once an organ of great importance in homeostasis maintaining. The search for herbal hepatoprotective capacity has been increasing, mainly because of the synthetic products used for this purpose may present adverse effects. Guaraná, obtained from the roasted seeds of the Amazonian plant Paullinia cupana var. sorbilis (Sapindaceae), is a product with a wide reputation as stimulant and a nutritional supplement in terms of physical and mental stress. It also presents several other biological properties, among them the antioxidant, antimicrobial, anticancer and anti-obesogenic. However, few studies focus on the potential hepatoprotective this plant. In this study, the protective effects of Paullinia cupana Mart. var. sorbilis (guaraná) on liver damage were evaluated in rats exposed to carbon tetrachloride (CCl4). Male Wistar rats were intra gastric pretreated with guaraná powder (100, 300 and 600 mg/Kg) or silymarin 100 mg/Kg daily for 14 days before treatment with a single dose of CCl4 (50% CCl4, 1 mL/Kg, intraperitoneally). Rats were sacrificed 24 h later, and blood samples were collected for assaying serum biochemical parameters. The hepatic tissue was removed to perform the comet assay. CCl4 induced liver damage and significantly increased the activities of Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) in serum. In addition, CCl4 increased the DNA damage index in hepatocytes. Pretreatment with guaraná in all concentrations was significantly effective in decreasing the ALT and AST activities when compared with CCl4 treated group. Furthermore, the treatment with guaraná 300 mg/Kg decreased DNA damage index. In addition, the DNA damage index showed a significant positive correlation with AST and ALT. These results indicate that guaraná has hepatoprotective activity and prevents the DNA strand breakage in CCl4-induced liver damage in rats. / As doenças hepáticas representam um grave problema de saúde, uma vez que acometem um órgão de grande importância na manutenção da homeostase. A busca por fitoterápicos com capacidade hepatoprotetora vem aumentando, principalmente pelo fato dos produtos sintéticos utilizados para esse fim apresentarem efeitos adversos. O guaraná, obtido das sementes torradas da planta amazônica Paullinia cupana var. sorbilis (Sapindaceae), é um produto com ampla reputação como estimulante e como suplemento nutricional em condições de estresse físico e mental. Além disso, apresenta outras diversas propriedades biológicas, entre estas destacam-se os efeitos antioxidantes, antimicrobianos, anticancerígenos e anti-obesogênicos. Entretanto, poucos estudos enfocam o possível potencial hepatoprotetor desta planta. Neste trabalho, os efeitos protetivos do guaraná sobre o dano hepático foram avaliados em ratos expostos ao tetracloreto de carbono (CCl4). Ratos Wistar machos foram pré-tratados (gavagem) com pó de guaraná (100, 300 e 600 mg/Kg) ou com silimaria 100 mg/Kg durante o período de 14 dias. No 14a dia, para a indução de hepatotoxidade, os animais receberam dose única, via intraperitonial de CCl4 (1 mL/Kg; 50%, diluído em azeite de oliva). Após 24 h, amostras de sangue foram coletadas via retro-orbital para avaliação de parâmetros bioquímicos, os animais sacrificados e o tecido hepático removido para a realização do ensaio cometa. O tratamento com CCl4 provocou dano hepático, demonstrado pela elevação signifivativa da atividade das enzimas aspartato aminoranferase (AST) e da alanina aminotransferase (ALT) no soro. Além disso promoveu um aumento significativo no índice de dano ao DNA. O pré-tratamento com guaraná, em todas as concentrações, foi significativamente efetivo em evitar a elevação da atividade de AST e ALT quando comparados ao grupo controle CCl4. O pré-tratamento com guaraná 300 mg/Kg promoveu uma diminuição no índice de dano ao DNA. O índice de dano no DNA mostrou signifivativa correlação positiva com as atividades de AST e ALT. Estes resultados indicam que o guaraná tem atividade hepatoprotetora e previne a quebra da fita do DNA em dano induzido por CCl4 em ratos.

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