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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.
71

Prevalência de HPV em tumores de cabeça e pescoço de São Paulo, Brasil / HPV prevalence in head and neck tumors from São Paulo, Brasil

Julio Cesar Betiol 04 September 2014 (has links)
INTRODUÇÃO: O papilomavírus humano (HPV) encontra-se amplamente distribuído na população mundial. Apesar da grande maioria das infecções serem transientes, assintomáticas e passíveis de regressão espontânea, a infecção persistente por tipos de alto risco de HPV é necessária para o desenvolvimento de neoplasias intraepiteliais cervicais. Uma vez que apenas uma pequena parcela das infecções progride à lesões malignas após um longo período desde o diagnóstico inicial de lesões precursoras, tem-se iniciado a busca por fatores que possam influenciar na progressão ou na eliminação destas manifestações iniciais. A variabilidade genética viral tem sido apontada como um dos fatores que interagem neste processo. Embora virtualmente todos os tumores da cérvice uterina apresentem o DNA viral, neoplasias em outros sítios anatômicos têm sido apenas em parte correlacionadas com a presença viral, sendo o HPV proposto como um dos agentes causadores de tumores em sítios de cabeça e pecoço. MÉTODOS: Espécimens clínicos de tumores de cabeça e pescoço, fixados em formalina e contidos em parafina (FFPE), provenientes do Instituto do Câncer do Estado de São Paulo (n=79) e da Santa Casa de Misericórida de São Paulo (n=94), tiveram seu DNA extraído, seguido de diagnóstico e genotipagem de HPV pela metodologia de Inno-LiPA. Análises de linhagens moleculares foram realizadas nas amostras HPV-16 positivas. Análise imunohistoquímica de P16INK4a foi realizada em todas as amostras. RESULTADOS: A presença do DNA viral foi encontrada em 24,1% (19/79) dentre a série de tumores provenientes do ICESP, sendo a cavidade oral o sítio em que foi observada a maior proporção de DNA viral (27,1%), enquanto que 13,8% (13/94) dentre os espécimens provenientes da Santa Casa apresentaram-se positivos para HPV, sendo a cavidade oral o sítio em que foi observada a maior proporção do DNA viral (18,1%). O HPV-16 foi o tipo mais prevalente, detectado em 73,4% das amostras HPV positivas provenientes do ICESP e 61,5% das amostras provenientes da Santa Casa. Independente da Instituição, as amostras foram alocadas no clado das linhagens Asiático-Americana e Europeia em 50%, cada uma, entre os 18 tumores HPV-16 positivos em que as análises de linhagem foram possíveis. Não foi observada, nestas séries, correlação entre a superexpressão de P16INK4a e a presença do DNA viral. CONCLUSÃO: Nas amostras analisadas, o DNA de HPV foi detectado em 18,5% dos 173 espécimens. O HPV-16 foi o tipo mais prevalente. Isolados da linhagem Europeia e da linhagem Asiatico-Americano foram detectados em 50% dos casos, cada uma, dentre as amostras HPV-16 analisadas por este estudo / INTRODUCTION: Human papillomaviruses (HPV) are widely distributed worldwide. Although the majority of infections are usually transient, asymptomatic and frequently regress spontaneously, persistent infections by high-risk HPVs are necessary for the development of cervical intraepithelial neoplasia. Once only a small proportion of infections progress to malignant lesions after a long period of time since the initial diagnosis of precursor lesions, the search for factors that might influence the progression or clearence of these early manifestations are currently under way. Viral genetic variability has been proposed as one of the factors interacting in this process. Although virtually all cervix tumors present the viral DNA, neoplasias from other anatomical sites have been only in part correlated with viral presence, and HPV has been proposed as one causative agent in tumors from head and neck sites. METHODS: Clinical specimens of formalin-fixed paraffin embedded head and neck tumors, provided by the Cancer Institute of São Paulo (n=79) and also by the Santa Casa de Misericórdia de São Paulo (n=94), were submitted to DNA extraction and further HPV diagnostic and genotyping by the Inno-LiPA methodology. Molecular lineages analyses were performed in all HPV-16 positive samples. P16INK4a immunohistochemical analyses were conducted in all samples. RESULTS: HPV DNA was detected among 24.1% (19/79) of samples provided by ICESP, tumors from oral cavity presented the highest viral positivity (27.1%), whereas 13,8% (13/94) of the samples from Santa Casa presented HPV DNA, tumors from the oral cavity also presented the highest HPV positivity with 18.1% of viral DNA presence. HPV-16 was the most prevalent type detected in 73.4% and 61.5% of HPV positive ICESP and Santa Casa samples, respectively. Irrespective of the Institution, samples submitted to lineage analyzes were allocated in the Asiatic-American and European phylogenetic branches in 50%, each one, among the 18 tumors HPV-16 positive for which lineage analysis was possible. No correlation between P16INK4a overexpression and HPV DNA presence was observed. CONCLUSION: In this study, HPV DNA was detected in 18.5% among 173 head and neck tumor specimens. HPV-16 was the most prevalent type. The European and the Asiatic-American lineage were detected in 50% of the cases, each one, among the cases HPV-16 positive analyzed
72

Human papillomavirus in recurrent respiratory papillomatosis, tonsillar and mobile tongue cancer

Loizou, Christos January 2016 (has links)
This thesis focuses on the effects of the human papillomavirus (HPV) in tonsillar cancer, mobile tongue cancer, and recurrent respiratory papillomatosis (RRP). The purpose was to characterize patients with RRP in northern Sweden in order to identify more care-intensive RRP patients and to describe the voice and quality of life aspects that follow RRP. Further aims were to confirm the expected increase of HPV-positive tonsillar cancer cases in northern Sweden, and to study the correlation between HPV, its surrogate marker p16 and HPV receptor syndecan-1 in both tonsillar cancer and mobile tongue cancer. A total of 27 consecutive patients with RRP were evaluated at 3 months postoperatively using the voice handicap index (VHI) and SF-36 questionnaires to assess the impact on life and voice in a RRP population. The values were compared to normative data. This report was further extended by examining consecutive data from 21 new patients in order to characterize RRP patients in northern Sweden. In order to study HPV DNA in tonsillar (n= 65) and mobile tongue cancer (n=109), HPV DNA was extracted from paraffin-embedded biopsies and detected by polymerase chain reaction using general primers Gp5+/6+ and CpI/IIG. Expression of HPV surrogate marker p16 and the HPV receptor syndecan-1 was analysed by immunohistochemistry. Patients that underwent more than one RRP surgery per year were younger than those treated less frequently and they had significantly impaired voice quality as compared to normal subjects. Females, patients with frequent surgical treatment sessions, and patients with the high-risk HPV subtypes scored significantly lower in several domains of the quality of life assessment as compared with normal subjects. Forty-eight RRP patients had a median age of 44.5 years; 71% were men and 29% females, preferentially infected with HPV6. Patients with high surgical treatment frequency/year showed more widespread RRP in the larynx compared to the patients treated less frequently. A total of 214 tonsillar cancer cases were identified. The vast majority were men. They had a median age of 58 years at diagnosis and expressed HPV as well as p16. The incidence of tonsillar cancer revealed a 2,7-fold increase in men between the years 1990 and 2013. The study demonstrates a strong association between p16 and HPV infection in tonsillar malignancies. These findings are in contrast to the mobile tongue cancer cases, where no evidence of HPV DNA could be detected although one-third showed p16 staining. This demonstrated a poor correlation between HPV and p16 in mobile tongue cancer. There was no difference in the expression of the primary HPV receptor, syndecan-1, between tonsillar and mobile tongue cancer. In conclusion, the frequency of RRP operations, age at onset, gender and subtype of the HPV may be used as factors to predict voice disability. RRP patients with high surgical treatment frequency were significantly younger and had a more widespread laryngeal disease compared to the low-frequency treated group. This study confirms the existence of a clinical RRP group, not primarily related to HPV subtype, but to a more care-intensive RRP population. Our findings identify a 2,7-fold increase in the incidence of tonsillar cancer, HPV and p16 in men between 1990-2013. We can use p16 to detect HPV in tonsillar cancer but not in tongue cancer. The introduction of vaccination against HPV may have a role in the prevention of specific HPV-subtype positive head and neck malignancies and recurrent respiratory papillomatosis since the current vaccine protects against HPV6, 11, 16, 18, 31, 33, 45, 52 and 58. Males will definitely benefit indirectly from vaccination of females, though males will still remain at risk of cancers associated with HPV. This highlights the need for sex-neutral vaccination strategy. Our intention is that this thesis will provide scientific data to support a gender-neutral vaccination and to develop simple tools to detect HPV in tonsillar cancer. / Syftet med avhandlingen är att beskriva effekterna av humant papillomvirus (HPV) vid cancer i halsmandlarna, cancer i tungan och vid luftvägspapillom. Totalt 27 patienter med luftvägspapillom (RRP) under åren 2004-2012 utvärderades 3 månader efter operationen med röst handikapp index (VHI) och livskvalitetformuläret SF-36. Resultaten jämfördes med normal data. Studiematerialet utökades med 21 patienter till totalt 48 RRP patienter i syfte att karakterisera patientgruppen i norra Sverige. För att studera HPV-DNA i tonsillcancer (n = 65) och i cancer i mobil del av tungan (n = 109) extraherades HPV-DNA från paraffininbäddade provbitar som sedan analyserades med PCR teknik och GP5 + / 6 + och CPI/IIG primer. Uttryck av surrogatmarkör p16 och HPV-receptorn syndekan -1 analyserades med immunhistokemi. RRP patienter hade en medianålder på 44,5 år; 71% var män och 29% kvinnor, företrädesvis infekterade med HPV6. Patienter som opererades mer än en gång per år var yngre än de som behandlats mindre ofta och hade en statistiskt sämre röstkvalitet än friska kontroller. Kvinnor, patienter med täta kirurgiska behandlingsintervall och högrisk-HPV hade signifikant sämre livskvalitet jämfört med friska kontroller. Patienter med hög kirurgisk behandlingsfrekvens per år var signifikant yngre och hade mer utbredd RRP sjukdom i luftstrupen, jämfört med gruppen med låg behandlingsfrekvens. Sammanlagt, 214 fall av halsmandelscancer identifierades i norra Sverige under åren 1990-2013; majoriteten var män, med en medianålder på 58 år och positiva för både HPV och p16. Andelen halsmandelscancer fall ökade med 2,7 gånger bland männen på 23 år. Vi fann ett starkt samband mellan uttryck av p16 och HPV infektion i halsmandelscancer men inte i HPV-negativ, delvis p16-positiv (33%) mobil tungcancer. Det fanns ingen skillnad i uttrycket av den primära HPV-receptorn, syndekan -1, jämförande tung-, och halsmandelscancer. Antalet RRP operationer, ålder vid insjuknandet, kön och genetisk variant av HPV kan användas som indikatorer för att förutsäga grad av röststörning. RRP patienter med hög kirurgisk behandlingsfrekvens var signifikant yngre och hade en mer utbredd luftvägssjukdom jämfört med RRP patienter som behandlas mindre ofta. Vi har identifierat en undergrupp av RRP patienter som inte primärt karakteriseras efter HPV virusets genetik utan av ett mer vårdintensivt förlopp. Den aktuella avhandlingen har identifierat en 2,7-faldig ökning av antalet halsmandelscancer hos män och ett starkt samband mellan p16 och HPV infektion i halsmandlar men inte i HPV-negativ tungcancer som inte korrelerar till p16 uttryck. Vi kan använda p16 för att påvisa HPV i tonsillcancer men inte i cancer i mobil tunga. Idag ingår HPV vaccination i det allmänna vaccinationsprogrammet för flickor. Vi förväntar oss en tydlig profylaktisk effekt avseende insjuknande i HPV-relaterad huvud- och hals cancer samt luftvägspapillom eftersom vaccinet skyddar mot HPV bl.a. 6, 11, 16 och 18. Män kommer definitivt att gynnas indirekt genom vaccination av kvinnor men kommer att ha fortsatt högre risk än kvinnor att insjukna i HPV relaterad cancer vilket understryker behovet av könsneutral vaccination. Vår avsikt med avhandlingen är att ge vetenskapligt stöd för könsneutralt vaccination och enkla metoder att påvisa halsmandelscancer.
73

The social relation to the environment in contemporary capitalism: theoretical reflections and empirical explorations

Cahen-Fourot, Louison January 2019 (has links) (PDF)
This paper analyses the socio-economic context into which environmental policies and ecological sentiments emerge through empirically studying the relation to the environment of different kinds of capitalism. The association and interaction of the relation to the environment with other key social relations, e.g. the labour-capital relations, are studied and discussed. To achieve this, I draw from Regulation Theory and augment its analytical framework with an explicit environmental dimension. I then conduct an empirical analysis of the diversity of contemporary capitalism including the social relation to the environment for a sample of thirty-seven OECD and BRICS countries. Five kinds of capitalism are identified: the Northern-continental European, the Southern-central European, the Anglo-Saxon and Pacific, the Emerging Countries and the Two Giants. A main result is the correspondence between ecology-prone social relations to the environment, labour oriented capital-labour relations and welfare-oriented states. However, the results show that countries that are the most ecology-prone are also the ones that have the most relocated their environmental impact, an observation consistent with the critical literature on the Environmental Kuznets Curve. / Series: Ecological Economic Papers
74

Estudo da influência do tempo de preparo e temperatura de armazenamento na imunorreatividade de amostras de câncer de colo uterino

Guterres, Cátia Moreira January 2017 (has links)
Introdução: O câncer de colo uterino é o quarto câncer mais comum no sexo feminino e um importante problema mundial de saúde pública. Recentemente, o uso de biomarcadores para melhorar a sensibilidade e especificidade do rastreamento e diagnóstico desta patologia passou a ter maior importância. Dentre estes, P16 e Ki67 passaram a ser largamente utilizados em imunohistoquímica de amostras preservadas em parafina. Entretanto, não se sabe qual a influência do tempo e temperatura de armazenamento de amostras previamente cortadas. Objetivo: O presente estudo tem por finalidade avaliar a influência do tempo de preparo e temperatura de armazenamento na imunorreatividade para P16 e Ki67 de cortes de amostras cervicais. Métodos: Amostras de blocos de parafina de câncer de colo uterino foram seccionadas e montadas em lâminas, de maneira seriada, no período de 9, 6, 3, 1 mês e tempo zero, sendo armazenadas em -20°C, 4°C e temperatura ambiente (TA). Todas as amostras então foram processadas ao mesmo tempo por imunohistoquímica para detecção de P16 e Ki67, sendo realizada leitura da mesma região do tumor nas diferentes condições. Resultados: Dos 10 casos de câncer de colo uterino, foram analisadas 75 regiões para P16 e Ki67 nas diferentes condições. A expressão de P16 e Ki67 não variou de maneira significativa ao longo do tempo nas diferentes condições de temperatura de armazenamento. Por exemplo, os cortes de 9 meses apresentaram a seguinte expressão quando armazenados a -20°C, 4°C e TA, respectivamente [mediana (p25-75)]: marcador P16 - 200 (160-300), 200 (180-300) e 200 (170-300), o que não foi estatisticamente diferente do corte em tempo zero, 200 (200-300), P=0,210; marcador Ki 67 - 210 (160-270), 210 (160-270) e 210 (145-270), o que também não foi estatisticamente diferente do corte em tempo zero, 240 (180-270), P=0,651. Conclusão: Não há influência significativa do tempo de preparo e temperatura de armazenamento de lâminas com material já cortado para a realização de imunohistoquímica posteriormente, no período de até 9 meses, para P16 e Ki67. Isto permite que, ao processarmos lâminas para HE e/ou outros marcadores, podemos reservar lâminas para posterior processamento com P16 e Ki67 sem prejuízo à imunorreatividade. / Introduction: Cervical cancer is the fourth most common cancer in women and a major public health problem in the world. Recently, the use of biomarkers to improve the sensitivity and specificity of the screening and diagnosis of this pathology has become more important. Among these, P16 and Ki67 became widely used in immunohistochemistry of samples preserved in paraffin. However, the influence of storage time and temperature of previously cut samples is not known. Aim: The aim of this study was to evaluate the influence of preparation time and storage temperature on the immunoreactivity for P16 and Ki67 of cervical specimens. Methods: Cervical cancer paraffin blocks were sectioned and mounted onto glass slides in 9, 6, 3, 1 month and zero time and stored at -20°C, 4°C and room temperature (RT). All slides were then processed at the same time by immunohistochemistry for the detection of P16 and Ki67, and the same tumor region was read under the different conditions. Results: Of the 10 cases of cervical cancer, 75 regions were analyzed for P16 and Ki67 under different conditions. Expression of P16 and Ki67 did not vary significantly over time at different storage temperature conditions. For example, the 9-month slides showed the following expression when stored at -20°C, 4°C and RT, respectively [median (p25-75)]: P16 - 200 (160-300), 200 (180-300) and 200 (170-300), which was not statistically different from zero time cut, 200 (200-300), P = 0.210; Ki 67 - 270 (160-270), 210 (160-270) and 210 (145-270), which was also not statistically different from zero-time cutoff, 240 (180-270), P = 0.651. Conclusion: There is no significant influence of the preparation time and storage temperature of slides of cervical cancer to be processed by immunohistochemistry later, in the period of up to 9 months, for P16 and Ki67. This allows, when processing slides for HE and / or other markers, we can reserve slides for further processing with P16 and Ki67 without impairing immunoreactivity.
75

Rôle du stress oxydant et des cassures de l’ADN dans l’émergence néoplasique post-sénescence / Role of oxidative DNA damage in post-senescence neoplastic emergence

Nassour, Joe 28 September 2015 (has links)
La sénescence est un état d’arrêt prolifératif mis en place par les cellules en réponse à des dommages à l’ADN. Elle est considérée comme un mécanisme de protection qui s’oppose à l’initiation et au développement d’un cancer. Or, les mécanismes de sénescence et la capacité des cellules à s’échapper de cet état et à générer des cellules transformées semblent varier selon les types cellulaires. Chez les kératinocytes humains normaux de peau (NHEKs), la sénescence est transitoire et débouche pour la plupart des cellules sur une mort par autophagie et, pour environ une sur dix mille, sur une émergence néoplasique post-sénescence. Les cellules émergentes présentent des caractères de transformation et accumulent des mutations et des délétions. Cet échappement néoplasique de la sénescence n’est jamais observé dans les fibroblastes normaux de peau (NHDFs) qui, au contraire, une fois en sénescence sont bloqués irréversiblement dans le cycle cellulaire.J’ai participé dans un premier temps à l’étude du rôle de l’autophagie dans la balance échappement néoplasique et mort des NHEKs sénescents. Nous avons pu démontrer que les progéniteurs de cellules néoplasiques ont une activité autophagique modérée plus faible que ceux qui subissent la mort. Ainsi, ils échappent à la mort par autophagie tout en gardant un niveau d’activité autophagique de ménage suffisant pour éliminer leurs composés altérés par le stress oxydant et être capable de ré-entrer en mitose.J’ai ensuite cherché à caractériser les dommages oxydants mutagènes impliqués dans l’échappement néoplasique. Ma stratégie a été d’analyser de façon comparative les NHEKs par rapport aux NHDFs, puisque les uns mais non les autres développent une émergence néoplasique. J’ai ainsi pu constater que le taux de cassures augmente à la sénescence dans les deux types cellulaires, mais que ces cassures sont de nature différente, uniquement des SSBs (Single Strand Breaks) pour les NHEKs et principalement des DSBs (Double Strand Breaks) pour les NHDFs. L’accumulation de DSBs à la sénescence des NHDFs s’accompagne d’une induction robuste de la voie DDR (DNA Damage Response), d’une activation la voie p53-p21 et d’un arrêt stable dans le cycle cellulaire. Dans le cas des NHEKs, l’augmentation du taux de SSBs est la conséquence de l’augmentation du niveau de stress oxydant et de la perte de l’expression et de l’activité de la PARP1. Ceci contribue à une agglomération aberrante de XRCC1 au niveau des cassures engendrant une induction de la voie p38MAPK - p16INK4a et un arrêt dans le cycle cellulaire caractéristique de la sénescence. D’une manière paradoxale, l’échappement néoplasique de la sénescence dépend également de cette accumulation de SSBs non réparés. Ainsi, la nature des dommages à l’ADN influence le devenir des cellules sénescentes. Les DSBs renforcent la stabilité de l’arrêt du cycle cellulaire alors que les SSBs promeuvent l’acquisition de mutations et l’échappement néoplasique. / Senescence is a permanent cell-cycle arrest activated in response to DNA damage. If a cell escapes from this state, it should inherit mutations and could potentially initiate a tumor. NHDFs (Normal Human Dermal Fibroblasts) display a classical irreversible and stable senescence plateau. In contrast, senescent NHEKs (Normal Human Epidermal Keratinocytes) experience two different outcomes. Most of them undergo autophagic cell death and about one on 10000 spontaneously resumes mitosis and generates clones of transformed, mutated and tumorigenic cells.I contributed in a first time to studying the role of macroautophagy in the cell death / post-senescence neoplastic emergence balance of senescent NHEKs. We have shown that macroautophagy plays antagonistic roles during senescence, inducing cell death or promoting neoplastic transformation, depending on its level of activation. Indeed, the progenitors of post-senescent emergent cells display oxidative stress and autophagic activity levels slightly lower than the average, what allows them to avoid autophagic cell death and to ensure the quality control indispensable for mitosis re-entry.Since oxidative stress is the motor of the post-senescence neoplastic emergence in NHEKs, I wondered next whether oxidative stress could operate through the generation of some mutagenic DNA damage. I took advantage of the comparison of senescent NHEKs to NHDFs. I have shown that unlike NHDFs, NHEKs do not suffer from significantly shortened telomeres, nor accumulate DSBs, do not activate a DDR (DNA Damage Response) pathway and in consequence do not significantly activate the p53/p21 pathway. Instead, they suffer from a decrease in PARP1 expression, which compromises the repair of SSBs generated by oxidative stress. In consequence, SSBR foci, precisely XRCC1 foci, become persistent. These persistent foci initiate a signalization, through p38MAPK, which leads to up-regulation of p16INK4A and to cell cycle arrest. Notably, the accumulation of unrepaired SSBs is sufficient for the post-senescence neoplastic emergence phenomenon, in addition, paradoxically to its involvement in the onset of senescence.In conclusion, senescence results from the persistence of a DNA damage signalization, but the exact nature of the damages could vary in different cell types depending on their repair capacities and could dictate completely different outcomes. Namely, persistent DSBs, including telomeric ones, dictate a permanent tumor-suppressor cell cycle arrest, whereas persistent SSBs are permissive to mutation and senescence evasion.
76

Developing nanobodies to stabilise the tumour suppressor protein p16INK4a

Burbidge, Owen David January 2019 (has links)
The tumour suppressor protein p16INK4a (p16) is a cyclin-dependent kinase (CDK) inhibitor that plays a key role in the regulation of the cell cycle by controlling the progression of cells through the G1 to S phase transition. Dysregulation of the protein through deletion, silencing or mutation of the gene encoding p16 is implicated in a range of different cancers including melanoma, cervical and oesophageal to name a few. p16 is composed of four ankyrin repeats and it has a very low thermodynamic and kinetic stability and rapidly unfolds even in the absence of denaturants. This low stability means that the protein is highly vulnerable to point mutations, which can result in functional inactivation through a range of different mechanisms such as deletion of key binding contacts, disruption of secondary or tertiary structure and consequent destabilisation leading to unfolding or aggregation. Heavy-chain antibodies are a unique form of antibody devoid of light chains found in the serum of the Camelid family (camels and llamas). Despite the absence of light chains, heavy-chain antibodies have evolved to complement traditional antibodies and retain the full binding capacity seen in canonical IgG antibodies. The single variable domain, known as a nanobody, is, at 15 kDa, the smallest antigen binding fragment, a tenth the size of a standard IgG antibody. The small size and relative ease of production, coupled with an unusually high stability, makes nanobodies useful tools as biological reagents, crystallography chaperones and therapeutics. The research contained within this PhD looks at the development of nanobodies to target p16. By leveraging the high stability of selected nanobodies, the aim was to obtain binders that could stabilise and reactivate a range of unstable cancer-associated mutants. The initial stages of the project focused on generating and optimising the expression and purification of p16 constructs prior to immunisation of animals to raise nanobodies. A high-throughput approach was taken to generate forty-five different p16 constructs with a range of different solubility and purification tags. These constructs were assessed in a multi-factorial expression screen, which resulted in the identification of a p16 construct with a ten-fold improvement in soluble expression levels compared with previous studies. A range of biophysical techniques, including circular dichroism and chemical denaturation, were performed to characterise this protein fully prior to immunisation. The second part of this project utilised a phage display library of two immune nanobody libraries generated against p16 and a p16 variant stabilised by previously published second-site mutations. This process yielded a large number of diverse nanobodies. Biophysical characterisation of these nanobodies was first performed, and they were found to have a range of chemical and thermal stabilities. Assays were then developed to test the ability of the nanobodies to stabilise p16. Two nanobodies were found to dramatically stabilise wild-type p16, with an increase in stability of approximately 44 % and 60 %, respectively. Furthermore, these nanobodies were also able to stabilise a subset of cancer-associated point mutants. Although there are NMR structures of p16, as well as a crystal structure of p16 bound to CDK6, the resolution of is very low, most likely due to the high backbone flexibility of p16. The last part of the project aimed to obtain a higher-resolution structure of p16 by using the two stabilising nanobodies as crystallisation chaperones. The more stabilising of the two nanobodies resulted in crystals that diffracted to a resolution of less than 2 $\AA$, a significant improvement compared with the previously published structure. In conclusion, a number of nanobodies were generated against tumour-associated p16 and shown to be capable of stabilising p16, allowing structure determination to high resolution and restoration of the stability of cancer-associated mutants to wild-type levels. In the project, a range of different approaches for nanobody production were explored, and these will be important for future applications. Moreover, the crystal structure of the p16-nanobody complex showed that the nanobody binds on the opposite face of p16, to the face involved in binding to CDKs; thus, this nanobody could potentially be exploited as a pharmacological chaperone to stabilise and restore the activity of cancer-associated mutant p16 in the cell.
77

Estudo da influência do tempo de preparo e temperatura de armazenamento na imunorreatividade de amostras de câncer de colo uterino

Guterres, Cátia Moreira January 2017 (has links)
Introdução: O câncer de colo uterino é o quarto câncer mais comum no sexo feminino e um importante problema mundial de saúde pública. Recentemente, o uso de biomarcadores para melhorar a sensibilidade e especificidade do rastreamento e diagnóstico desta patologia passou a ter maior importância. Dentre estes, P16 e Ki67 passaram a ser largamente utilizados em imunohistoquímica de amostras preservadas em parafina. Entretanto, não se sabe qual a influência do tempo e temperatura de armazenamento de amostras previamente cortadas. Objetivo: O presente estudo tem por finalidade avaliar a influência do tempo de preparo e temperatura de armazenamento na imunorreatividade para P16 e Ki67 de cortes de amostras cervicais. Métodos: Amostras de blocos de parafina de câncer de colo uterino foram seccionadas e montadas em lâminas, de maneira seriada, no período de 9, 6, 3, 1 mês e tempo zero, sendo armazenadas em -20°C, 4°C e temperatura ambiente (TA). Todas as amostras então foram processadas ao mesmo tempo por imunohistoquímica para detecção de P16 e Ki67, sendo realizada leitura da mesma região do tumor nas diferentes condições. Resultados: Dos 10 casos de câncer de colo uterino, foram analisadas 75 regiões para P16 e Ki67 nas diferentes condições. A expressão de P16 e Ki67 não variou de maneira significativa ao longo do tempo nas diferentes condições de temperatura de armazenamento. Por exemplo, os cortes de 9 meses apresentaram a seguinte expressão quando armazenados a -20°C, 4°C e TA, respectivamente [mediana (p25-75)]: marcador P16 - 200 (160-300), 200 (180-300) e 200 (170-300), o que não foi estatisticamente diferente do corte em tempo zero, 200 (200-300), P=0,210; marcador Ki 67 - 210 (160-270), 210 (160-270) e 210 (145-270), o que também não foi estatisticamente diferente do corte em tempo zero, 240 (180-270), P=0,651. Conclusão: Não há influência significativa do tempo de preparo e temperatura de armazenamento de lâminas com material já cortado para a realização de imunohistoquímica posteriormente, no período de até 9 meses, para P16 e Ki67. Isto permite que, ao processarmos lâminas para HE e/ou outros marcadores, podemos reservar lâminas para posterior processamento com P16 e Ki67 sem prejuízo à imunorreatividade. / Introduction: Cervical cancer is the fourth most common cancer in women and a major public health problem in the world. Recently, the use of biomarkers to improve the sensitivity and specificity of the screening and diagnosis of this pathology has become more important. Among these, P16 and Ki67 became widely used in immunohistochemistry of samples preserved in paraffin. However, the influence of storage time and temperature of previously cut samples is not known. Aim: The aim of this study was to evaluate the influence of preparation time and storage temperature on the immunoreactivity for P16 and Ki67 of cervical specimens. Methods: Cervical cancer paraffin blocks were sectioned and mounted onto glass slides in 9, 6, 3, 1 month and zero time and stored at -20°C, 4°C and room temperature (RT). All slides were then processed at the same time by immunohistochemistry for the detection of P16 and Ki67, and the same tumor region was read under the different conditions. Results: Of the 10 cases of cervical cancer, 75 regions were analyzed for P16 and Ki67 under different conditions. Expression of P16 and Ki67 did not vary significantly over time at different storage temperature conditions. For example, the 9-month slides showed the following expression when stored at -20°C, 4°C and RT, respectively [median (p25-75)]: P16 - 200 (160-300), 200 (180-300) and 200 (170-300), which was not statistically different from zero time cut, 200 (200-300), P = 0.210; Ki 67 - 270 (160-270), 210 (160-270) and 210 (145-270), which was also not statistically different from zero-time cutoff, 240 (180-270), P = 0.651. Conclusion: There is no significant influence of the preparation time and storage temperature of slides of cervical cancer to be processed by immunohistochemistry later, in the period of up to 9 months, for P16 and Ki67. This allows, when processing slides for HE and / or other markers, we can reserve slides for further processing with P16 and Ki67 without impairing immunoreactivity.
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Estudo da influência do tempo de preparo e temperatura de armazenamento na imunorreatividade de amostras de câncer de colo uterino

Guterres, Cátia Moreira January 2017 (has links)
Introdução: O câncer de colo uterino é o quarto câncer mais comum no sexo feminino e um importante problema mundial de saúde pública. Recentemente, o uso de biomarcadores para melhorar a sensibilidade e especificidade do rastreamento e diagnóstico desta patologia passou a ter maior importância. Dentre estes, P16 e Ki67 passaram a ser largamente utilizados em imunohistoquímica de amostras preservadas em parafina. Entretanto, não se sabe qual a influência do tempo e temperatura de armazenamento de amostras previamente cortadas. Objetivo: O presente estudo tem por finalidade avaliar a influência do tempo de preparo e temperatura de armazenamento na imunorreatividade para P16 e Ki67 de cortes de amostras cervicais. Métodos: Amostras de blocos de parafina de câncer de colo uterino foram seccionadas e montadas em lâminas, de maneira seriada, no período de 9, 6, 3, 1 mês e tempo zero, sendo armazenadas em -20°C, 4°C e temperatura ambiente (TA). Todas as amostras então foram processadas ao mesmo tempo por imunohistoquímica para detecção de P16 e Ki67, sendo realizada leitura da mesma região do tumor nas diferentes condições. Resultados: Dos 10 casos de câncer de colo uterino, foram analisadas 75 regiões para P16 e Ki67 nas diferentes condições. A expressão de P16 e Ki67 não variou de maneira significativa ao longo do tempo nas diferentes condições de temperatura de armazenamento. Por exemplo, os cortes de 9 meses apresentaram a seguinte expressão quando armazenados a -20°C, 4°C e TA, respectivamente [mediana (p25-75)]: marcador P16 - 200 (160-300), 200 (180-300) e 200 (170-300), o que não foi estatisticamente diferente do corte em tempo zero, 200 (200-300), P=0,210; marcador Ki 67 - 210 (160-270), 210 (160-270) e 210 (145-270), o que também não foi estatisticamente diferente do corte em tempo zero, 240 (180-270), P=0,651. Conclusão: Não há influência significativa do tempo de preparo e temperatura de armazenamento de lâminas com material já cortado para a realização de imunohistoquímica posteriormente, no período de até 9 meses, para P16 e Ki67. Isto permite que, ao processarmos lâminas para HE e/ou outros marcadores, podemos reservar lâminas para posterior processamento com P16 e Ki67 sem prejuízo à imunorreatividade. / Introduction: Cervical cancer is the fourth most common cancer in women and a major public health problem in the world. Recently, the use of biomarkers to improve the sensitivity and specificity of the screening and diagnosis of this pathology has become more important. Among these, P16 and Ki67 became widely used in immunohistochemistry of samples preserved in paraffin. However, the influence of storage time and temperature of previously cut samples is not known. Aim: The aim of this study was to evaluate the influence of preparation time and storage temperature on the immunoreactivity for P16 and Ki67 of cervical specimens. Methods: Cervical cancer paraffin blocks were sectioned and mounted onto glass slides in 9, 6, 3, 1 month and zero time and stored at -20°C, 4°C and room temperature (RT). All slides were then processed at the same time by immunohistochemistry for the detection of P16 and Ki67, and the same tumor region was read under the different conditions. Results: Of the 10 cases of cervical cancer, 75 regions were analyzed for P16 and Ki67 under different conditions. Expression of P16 and Ki67 did not vary significantly over time at different storage temperature conditions. For example, the 9-month slides showed the following expression when stored at -20°C, 4°C and RT, respectively [median (p25-75)]: P16 - 200 (160-300), 200 (180-300) and 200 (170-300), which was not statistically different from zero time cut, 200 (200-300), P = 0.210; Ki 67 - 270 (160-270), 210 (160-270) and 210 (145-270), which was also not statistically different from zero-time cutoff, 240 (180-270), P = 0.651. Conclusion: There is no significant influence of the preparation time and storage temperature of slides of cervical cancer to be processed by immunohistochemistry later, in the period of up to 9 months, for P16 and Ki67. This allows, when processing slides for HE and / or other markers, we can reserve slides for further processing with P16 and Ki67 without impairing immunoreactivity.
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Regulators of hypoxia response and the cell cycle in breast cancer

Peurala, E. (Emmi) 19 November 2013 (has links)
Abstract Breast cancer is the most common cancer affecting the female population of the Western world. It is a heterogeneous disease entity that encompasses tumors with remarkably different forms of behaviour, and it is therefore vital to distinguish patients with good and poor prognoses. The classical prognostic and predictive factors for breast cancer serve as tools for clinical oncologists when planning treatment, but the growing awareness of breast cancer biology is bringing about a need for novel prognostic and predictive biomarkers. This thesis examines the prognostic significance of hypoxia response and cell cycle regulators in ductal breast cancer and in triple-negative breast cancer (negative for hormone receptors and human epidermal growth factor receptor 2), concluding that PHD2 and PHD3 are associated with a good prognosis, while the role of PHD1 is controversial, as it is associated with proliferation in ductal breast cancer but with node-negative status in triple-negative breast cancer. In our experiments HIF-1α redeemed its role as a marker of an adverse prognosis, whereas the role of HIF-2α appeared to be the opposite. Our data suggest that PHDs can have other targets than the HIF-αs, and that triple-negative breast tumors express more HIF-1α and less HIF-2α and PHD3 than those with a good prognosis. Furthermore, we identified cyclin D1 as a biomarker with independent prognostic significance in ductal breast cancer, being associated with good prognostic factors and a better outcome, whereas the opposite was seen in triple-negative breast cancer. CDK4 was associated with high proliferation in triple-negative breast cancer. In addition, high levels of p16 correlated with increased survival in breast cancer patients independently of receptor status. / Tiivistelmä Rintasyöpä on naisten yleisin syöpä läntisessä maailmassa. Rintasyöpä on heterogeeninen tautiryhmä, jossa kasvaimet vaihtelevat biologiselta käyttäytymiseltään huomattavasti. Tästä syystä on tärkeää erottaa hyvä- ja huonoennusteiset potilaat. Syöpälääkärit käyttävät klassisia ennustetekijöitä hoitopäätöksiä tehdessään, mutta lisääntynyt tieto rintasyövän biologiasta on saanut aikaan tarpeen löytää uusia ennustetekijöitä. Tässä väitöskirjatyössä tutkimme hypoksiavasteen ja solusyklin säätelijöiden ennusteellisuutta duktaalisessa rintasyövässä sekä kolmoisnegatiivisessa (ei ilmennä hormonireseptoreita eikä epidermaalikasvutekijäreseptoria) rintasyövässä. PHD2 ja PHD3:n vahva ilmentyminen liittyi parempaan ennusteeseen, mutta PHD1:n esiintymisen vaikutus oli ristiriitainen. PHD1:n ilmentyminen liittyi lisääntyneeseen solujakautumiseen duktaalisessa rintasyövässä, mutta kolmoisnegatiivisessa rintasyövässä sen esiintyminen liittyi vähentyneeseen imusolmukemetastasointiin. Tutkimuksessamme HIF-1α osoittautui huonon ennusteen merkiksi. Sitä vastoin HIF-2α:n ilmentymisen vaikutus näytti liittyvän parempaan ennusteeseen. Tuloksemme osoittavat, että PHD-entsyymeillä on mahdollisesti muitakin kohteita kuin HIF-α:t. Osoitimme myös, että HIF-1α:n ilmentyminen on yleisempää ja HIF-2α:n sekä PHD3:n ilmentyminen vähäisempää kolmoisnegatiivisessa kuin duktaalisessa rintasyövässä. Lisäksi totesimme, että sykliini D1 on itsenäinen ennustetekijä liittyen parempaan ennusteeseen duktaalisessa rintasyövässä. Huomioitavaa on kuitenkin, että kolmoisnegatiivisessa rintasyövän alaryhmässä sykliini D1:n esiintyminen oli huonon ennusteen merkki. CDK4 osoittautui voimakkaan proliferaation merkiksi kolmoisnegatiivisessa rintasyövässä. Lisäksi osoitimme, että p16:n ilmentyminen liittyy parempaan ennusteeseen sekä duktaalisessa rintasyövässä että kolmoisnegatiivisessa rintasyövässä.
80

Analysis of cellular retinoic acid binding protein 2 expression in dermal fibroblasts; role in non-healing of chronic wounds

Amjad, Arshi January 2017 (has links)
Abstract Chronic, non-healing wounds constitute a massive financial burden on health care system. The healing processes of these wounds and their underlying pathology are only partly understood. In this study, important biological functions performed by Retinoic acid with its regulatory protein cellular retinoic acid binding protein 2 (CRABP2) were discussed. Possibly, these biological func-tions might be linked with chronic wound therapeutic by inducing antiproliferative activity of cells which leads to reduction in migration and growth rate of fibroblast during skin regeneration pro-cess in chronic wound healing. The aim of this study was to comparatively analyze the expression pattern of CRABP2 and P16 cyclic dependent kinase inhibitor in dermal fibroblasts at mRNA levels along with their morphological pattern, migration and growth rate. Fibroblasts were cultured and their morphology were observed by phase-contrast imaging. Difference in viability, migratory capacity was examined by Cell titer blue and scratch assay respectively and expression were meas-ured by polymerase chain reaction. Interestingly, the date revealed that morphology was altered and growth rate and migration velocity was significantly lower in chronic wound fibroblasts and senescent fibroblasts when compared with their control. Expression pattern revealed that CRABP2 was highly up-regulated only by senescent cells but not in chronic wound fibroblasts which point novel function for this protein in term of replicative senescence. However, P16 was not signifi-cantly altered among all fibroblasts which demands supplementary studies to conform the role of CRABP2 in fibroblast dysfunction and cellular senescence in chronic wounds.

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