944 resultados para clinical progression
Resumo:
In work integrated learning, students may report difficulties applying theory learned at university to clinical practice. One contributing factor may be students' inability to engage in meaningful reflection and self-correcting behaviours. This paper reports the evaluation of a tool, process and resources developed to assist students to reflect on feedback and engage in self-assessment. Students were assisted to develop self-assessment skills by reflecting on, and engaging with feedback from previous workplace experiences to develop goals, learning outcomes and strategies to improve performance with mostly positive results. A secondary aim was to identify common learning strategies or barriers that impacted on student outcomes. Four themes emerged from the qualitative data: 1) preparing for clinical learning; 2) relationships and engagement levels; 3) shared awareness, and; 4) developing clinical practice. Overall students felt the tool assisted them to narrow their attention on what needed to be improved. While supervisors believed the tool helped them to focus on specific needs of each student. Common barriers to clinical practice improvement related to a lack of opportunity in some settings, and lack of staff willingness to support students to achieve identified goals. Students and supervisors found the use of the tools beneficial and assisted students to demonstrate a greater understanding of how to apply feedback received to support their learning in the clinical environment.
Resumo:
Virotherapy, the use of oncolytic properties of viruses for eradication of tumor cells, is an attractive strategy for treating cancers resistant to traditional modalities. Adenoviruses can be genetically modified to selectively replicate in and destroy tumor cells through exploitation of molecular differences between normal and cancer cells. The lytic life cycle of adenoviruses results in oncolysis of infected cells and spreading of virus progeny to surrounding cells. In this study, we evaluated different strategies for improving safety and efficacy of oncolytic virotherapy against human ovarian adenocarcinoma. We examined the antitumor efficacy of Ad5/3-Δ24, a serotype 3 receptor-targeted pRb-p16 pathway-selective oncolytic adenovirus, in combination with conventional chemotherapeutic agents. We observed synergistic activity in ovarian cancer cells when Ad5/3-Δ24 was given with either gemcitabine or epirubicin, common second-line treatment options for ovarian cancer. Our results also indicate that gemcitabine reduces the initial rate of Ad5/3-Δ24 replication without affecting the total amount of virus produced. In an orthotopic murine model of peritoneally disseminated ovarian cancer, combining Ad5/3-Δ24 with either gemcitabine or epirubicin resulted in greater therapeutic benefit than either agent alone. Another useful approach for increasing the efficacy of oncolytic agents is to arm viruses with therapeutic transgenes such as genes encoding prodrug-converting enzymes. We constructed Ad5/3-Δ24-TK-GFP, an oncolytic adenovirus encoding the thymidine kinase (TK) green fluorescent protein (GFP) fusion protein. This novel virus replicated efficiently on ovarian cancer cells, which correlated with increased GFP expression. Delivery of prodrug ganciclovir (GCV) immediately after infection abrogated viral replication, which might have utility as a safety switch mechanism. Oncolytic potency in vitro was enhanced by GCV in one cell line, and the interaction was not dependent on scheduling of the treatments. However, in murine models of metastatic ovarian cancer, administration of GCV did not add therapeutic benefit to this highly potent oncolytic agent. Detection of tumor progression and virus replication with bioluminescence and fluorescence imaging provided insight into the in vivo kinetics of oncolysis in living mice. For optimizing protocols for upcoming clinical trials, we utilized orthotopic murine models of ovarian cancer to analyze the effect of dose and scheduling of intraperitoneally delivered Ad5/3-Δ24. Weekly administration of Ad5/3-Δ24 did not significantly enhance antitumor efficacy over a single treatment. Our results also demonstrate that even a single intraperitoneal injection of only 100 viral particles significantly increased the survival of mice compared with untreated animals. Improved knowledge of adenovirus biology has resulted in creation of more effective oncolytic agents. However, with more potent therapy regimens an increase in unwanted side-effects is also possible. Therefore, inhibiting viral replication when necessary would be beneficial. We evaluated the antiviral activity of chlorpromazine and apigenin on adenovirus replication and associated toxicity in fresh human liver samples, normal cells, and ovarian cancer cells. Further, human xenografts in mice were utilized to evaluate antitumor efficacy, viral replication, and liver toxicity. Our data suggest that these agents can reduce replication of adenoviruses, which could provide a safety switch in case of replication-associated side-effects. In conclusion, we demonstrate that Ad5/3-Δ24 is a useful oncolytic agent for treatment of ovarian cancer either alone or in combination with conventional chemotherapeutic drugs. Insertion of genes encoding prodrug-converting enzymes into the genome of Ad5/3-Δ24 might not lead to enhanced antitumor efficacy with this highly potent oncolytic virus. As a safety feature, viral activity can be inhibited with pharmacological substances. Clinical trials are however needed to confirm if these preclinical results can be translated into efficacy in humans. Promising safety data seen here, and in previous publications suggest that clinical evaluation of the agent is feasible.
Resumo:
Paracrine regulation between the components of the tumour microenvironment cancer cells, activated fibroblasts, immune and endothelial cells is under intense investigation. The signals between the different cell types are mediated by soluble factors, such as growth factors, proinflammatory cytokines and proteolytic enzymes. Nemosis is an experimental in vitro model of fibroblast activation, leading to increased production of such mediators. Nemotic activation of fibroblasts occurs as they are forced to cluster thereby forming a multicellular spheroid. The aim of the present studies was to elucidate the mechanisms underlying the nemotic response of cancer-associated fibroblasts (CAF) and the role of nemosis in paracrine regulation between activated fibroblasts and benign and malignant epithelial cells. The results presented in this thesis demonstrate that the nemotic response of CAFs and normal fibroblasts differs, and inter-individual variations exist between fibroblast populations. In co-culture experiments, fibroblasts increased colony formation of squamous cell carcinoma (SCC) cells, and CAFs further augmented this, highlighting the tumour-evolving properties of CAFs. Furthermore, fibroblast monolayers in those co-cultures started to cluster spontaneously. This kind of spontaneous nemosis response might take place also in vivo, although more direct evidence of this still needs to be obtained. The HaCaT skin carcinoma progression model was used to study the effects of benign and malignant keratinocytes on fibroblast nemosis. Benign HaCaT cells inhibited fibroblast nemosis, observed as inhibition of cyclooxygenase 2 (COX-2) induction in nemotic spheroids. In contrast, malignant HaCaTs further augmented the nemotic response by increasing expression of COX-2 and the growth factors hepatocyte growth factor / scatter factor (HGF/SF) and vascular endothelial growth factor (VEGF), as well as causing a myofibroblastic differentiation of nemotic fibroblasts into fibroblasts resembling CAFs. On the other side of this reciprocal signalling, factors secreted into conditioned medium by the nemotic fibroblasts promoted proliferation and motility of the HaCaT cell lines. Notably, the nemotic fibroblast medium increased the expression of p63, a transcription factor linked to carcinogenesis, also in the highly metastatic HaCaT cells. These results emphasize the paracrine role of factors secreted by activated fibroblasts in driving tumour progression. We also investigated the epithelial-mesenchymal transition (EMT) of the HaCaT clones in response to transforming growth factor β (TGF-β), which is a well-characterized inducer of EMT. TGF-β caused growth arrest and loss of epithelial cell junctions in the HaCaT derivatives, but mesenchymal markers were not induced, suggesting a partial, but not complete EMT response. Inflammation induced by COX-2 has been proposed to be a key mechanism in EMT of benign cells. Corroborating this notion, COX-2 was induced only in benign, not in malignant HaCaT derivatives. Furthermore, in cells in which TGF-β caused COX-2 induction, migration was clearly augmented. The concept of treating cancer is changing from targeting solely the cancer cells to targeting the whole microenvironment. The results of this work emphasise the role of activated fibroblasts in cancer progression and that CAFs should also be taken into consideration in the treatment of cancer. The results from these studies suggests that nemosis could be used as a diagnostic tool to distinguish in vitro activated fibroblasts from tumour stroma and also in studying the paracrine signalling that is mediated to other cell types via soluble factors.
Resumo:
Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare, dominantly inherited tumor predisposition syndrome characterized by benign cutaneous and uterine (ULM) leiomyomas, and sometimes renal cell cancer (RCC). A few cases of uterine leiomyosarcoma (ULMS) have also been reported. Mutations in a nuclear gene encoding fumarate hydratase (FH), an enzyme of the mitochondrial tricarboxylic acid cycle (TCA cycle), underlie HLRCC. As a recessive condition, germline mutations in FH predispose to a neurological defect, FH deficiency (FHD). Hereditary paragangliomatosis (HPGL) is a dominant disorder associated with paragangliomas and pheochromocytomas. Inherited mutations in three genes encoding subunits of succinate dehydrogenase (SDH), also a TCA cycle enzyme, predispose to HPGL. Both FH and SDH seem to act as tumor suppressors. One of the consequences of the TCA cycle defect is abnormal activation of HIF1 pathway ( pseudohypoxia ) in the HLRCC and HPGL tumors. HIF1 drives transcription of genes encoding e.g. angiogenetic factors which can facilitate tumor growth. Recently hypoxia/HIF1 has been suggested to be one of the causes of genetic instability as well. One of the aims of this study was to broaden the clinical definers of HLRCC. To determine the cancer risk and to identify possible novel tumor types associated with FH mutations eight Finnish HLRCC/FHD families were extensively evaluated. The extension of the pedigrees and the Finnish Cancer Registry based tumor search yielded genealogical and cancer data of altogether 868 individuals. The standardized incidence ratio-based comparison of HLRCC/FHD family members with general Finnish population revealed 6.5-fold risk for RCC. Moreover, risk for ULMS was highly increased. However, according to the recent and more stringent diagnosis criteria of ULMS many of the HLRCC uterine tumors previously considered malignant are at present diagnosed as atypical or proliferative ULMs (with a low risk of recurrence). Thus, the formation of ULMS (as presently defined) in HLRCC appears to be uncommon. Though increased incidence was not observed, interestingly the genetic analyses suggested possible association of breast and bladder cancer with loss of FH. Moreover, cancer cases were exceptionally detected in an FHD family. Another clinical finding was the conventional (clear cell) type RCC of a young Spanish HLRCC patient. Conventional RCC is distinct from the types previously observed in this syndrome but according to these results, FH mutation may underlie some of young conventional cancer cases. Secondly, the molecular pathway from defective TCA cycle to tumor formation was intended to clarify. Since HLRCC and HPGL tumors display abnormally activated HIF1, the hypothesis on the link between HIF1/hypoxia and genetic instability was of interest to study in HLRCC and HPGL tumor material. HIF1α (a subunit of HIF1) stabilization was confirmed in the majority of the specimens. However, no repression of MSH2, a protein of DNA mismatch repair system, or microsatellite instability (MSI), an indicator of genetic instability, was observed. Accordingly, increased instability seems not to play a role in the tumorigenesis of pseudohypoxic TCA cycle-deficient tumors. Additionally, to study the putative alternative functions of FH, a recently identified alternative FH transcript (FHv) was characterized. FHv was found to contain instead of exon 1, an alternative exon 1b. Differential subcellular distribution, lack of FH enzyme activity, low mRNA expression compared to FH, and induction by cellular stress suggest FHv to have a role distinct from FH, for example in apoptosis or survival. However, the physiological significance of FHv requires further elucidation.
Resumo:
Human central nervous system (CNS) tumors are a heterogeneous group of tumors occurring in brain, brainstem and spinal cord. Malignant gliomas (astrocytic and oligodendroglial tumors), which arise from the neuroepithelial cells are the most common CNS neoplasms in human. Malignant gliomas are highly aggressive and invasive tumors, and have a very poor prognosis. The development and progression of gliomas involve a stepwise accumulation of genetic alterations that generally affect either signal transduction pathways activated by receptor tyrosine kinases (RTKs), or cell cycle arrest pathways. Constitutive activation or deregulated signaling by RTKs is caused by gene amplification, overexpression or mutations. The aberrant RTK signaling results in turn in the activation of several downstream pathways, which ultimately lead to malignant transformation and tumor proliferation. Many genetic abnormalities implicated in nervous system tumors involve the genes located at the chromosomal region 4q12. This locus harbors the receptor tyrosine kinases KIT, PDGFRA and VEGFR2, and other genes (REST, LNX1) with neural function. Gene amplification and protein expression of KIT, PDGFRA, and VEGFR2 was studied using clinical tumor material. REST and LNX1, as well as NUMBL, the interaction partner of LNX1, were studied for their gene mutations and amplifications. In our studies, amplification of LNX1 was associated with KIT and PDGFRA amplification in glioblastomas, and coamplification of KIT, PDGFRA and VEGFR2 was detected in medulloblastomas and CNS primitive neuroectodermal tumors. PDGFRA amplification was also correlated with poor overall survival. Coamplification of KIT, PDGFRA and VEGFR2 was observed in a subset of human astrocytic and oligodendroglial tumors. We suggest that genes at 4q12 could be a part of a larger amplified region, which is deregulated in gliomas, and could be used as a prognostic marker of tumorigenic process. The signaling pathways activated due to gene amplifications, activating gene mutations, and overexpressed proteins may be useful as therapeutic targets for glioma treatment. This study also includes the characterization of KIT overexpressing astrocytes, analyzed by various in vitro functional assays. Our results show that overexpression of KIT in mouse astrocytes promotes cell proliferation and anchorage-independent growth, as well as phenotypic changes in the cells. Furthermore, the increased proliferation is partly inhibited by imatinib, a small molecule inhibitor of KIT. These results suggest that KIT may play a role in astrocyte growth regulation, and might have an oncogenic role in brain tumorigenesis. Elucidation of the altered signaling pathways due to specific gene amplifications, activating gene mutations, and overexpressed proteins may be useful as therapeutic targets for glioma treatment.
Resumo:
Rituximab, a monoclonal antibody against B-cell specific CD20 antigen, is used for the treatment of non-Hodgkin lymphomas (NHL) and chronic lymphatic leukemia. In combination with chemotherapeutics rituximab has remarkably improved the outcome of NHL patients, but a vast variation in the lengths of remissions remains and the outcome of individual patients is difficult to predict. This thesis has searched for an explanation for this by studying the effector mechanisms of rituximab and by comparing gene expression in lymphoma tissue samples of patients with long- and short-term survival. This work demonstrated that activation of complement (C) system is in vitro more efficient effector mechanism of rituximab than cellular mechanisms or apoptosis. Activation of the C system was also shown in vivo during rituximab treatment. However, intravenously administered rituximab could not enter the cerebrospinal fluid, and neither C activation nor removal of lymphoma cells was observed in central nervous system. In vitro cytotoxicity assays showed that rituximab-induced cell killing could be markedly improved with simultaneous neutralization of the C regulatory proteins CD46 (Membrane cofactor protein), CD55 (Decay-accelerating factor), and CD59 (protectin). In a retrospective study of follicular lymphoma (FL) patients, low lymphoma tissue mRNA expressions of CD59 and CD55 were associated with a good prognosis and in a progressive flow cytometry study high expression of CD20 relative to CD55 was correlated to a longer progression free survival. Gene expression profile analysis revealed that expression of certain often cell cycle, signal transduction or immune response related genes correlate with clinical outcome of FL patients. Emphasizing the role of tumor microenvironment the best differentiating genes Smad1 and EphA1 were demonstrated to be mainly expressed in the non-malignant cells of tumors. In conclusion, this thesis shows that activation of the C system is a clinically important effector mechanism of rituximab and that microenvironment factor in tumors and expression of C regulatory proteins affect markedly the efficacy of immunochemotherapy. This data can be used to identify more accurately the patients for whom immunochemotherapy is given. It may also be beneficial in development of rituximab-containing and other monoclonal antibody therapies against cancer.
Resumo:
Helicobacter pylori infection is a risk factor for gastric cancer, which is a major health issue worldwide. Gastric cancer has a poor prognosis due to the unnoticeable progression of the disease and surgery is the only available treatment in gastric cancer. Therefore, gastric cancer patients would greatly benefit from identifying biomarker genes that would improve diagnostic and prognostic prediction and provide targets for molecular therapies. DNA copy number amplifications are the hallmarks of cancers in various anatomical locations. Mechanisms of amplification predict that DNA double-strand breaks occur at the margins of the amplified region. The first objective of this thesis was to identify the genes that were differentially expressed in H. pylori infection as well as the transcription factors and signal transduction pathways that were associated with the gene expression changes. The second objective was to identify putative biomarker genes in gastric cancer with correlated expression and copy number, and the last objective was to characterize cancers based on DNA copy number amplifications. DNA microarrays, an in vitro model and real-time polymerase chain reaction were used to measure gene expression changes in H. pylori infected AGS cells. In order to identify the transcription factors and signal transduction pathways that were activated after H. pylori infection, gene expression profiling data from the H. pylori experiments and a bioinformatics approach accompanied by experimental validation were used. Genome-wide expression and copy number microarray analysis of clinical gastric cancer samples and immunohistochemistry on tissue microarray were used to identify putative gastric cancer genes. Data mining and machine learning techniques were applied to study amplifications in a cross-section of cancers. FOS and various stress response genes were regulated by H. pylori infection. H. pylori regulated genes were enriched in the chromosomal regions that are frequently changed in gastric cancer, suggesting that molecular pathways of gastric cancer and premalignant H. pylori infection that induces gastritis are interconnected. 16 transcription factors were identified as being associated with H. pylori infection induced changes in gene expression. NF-κB transcription factor and p50 and p65 subunits were verified using elecrophoretic mobility shift assays. ERBB2 and other genes located in 17q12- q21 were found to be up-regulated in association with copy number amplification in gastric cancer. Cancers with similar cell type and origin clustered together based on the genomic localization of the amplifications. Cancer genes and large genes were co-localized with amplified regions and fragile sites, telomeres, centromeres and light chromosome bands were enriched at the amplification boundaries. H. pylori activated transcription factors and signal transduction pathways function in cellular mechanisms that might be capable of promoting carcinogenesis of the stomach. Intestinal and diffuse type gastric cancers showed distinct molecular genetic profiles. Integration of gene expression and copy number microarray data allowed the identification of genes that might be involved in gastric carcinogenesis and have clinical relevance. Gene amplifications were demonstrated to be non-random genomic instabilities. Cell lineage, properties of precursor stem cells, tissue microenvironment and genomic map localization of specific oncogenes define the site specificity of DNA amplifications, whereas labile genomic features define the structures of amplicons. These conclusions suggest that the definition of genomic changes in cancer is based on the interplay between the cancer cell and the tumor microenvironment.
Resumo:
Abnormal expansion or depletion of particular lymphocyte subsets is associated with clinical manifestations such as HIV progression to AIDS and autoimmune disease. We sought to identify genetic predictors of lymphocyte levels and reasoned that these may play a role in immune-related diseases. We tested 2.3 million variants for association with five lymphocyte subsets, measured in 2538 individuals from the general population, including CD4+ T cells, CD8+ T cells, CD56+ natural killer (NK) cells, and the derived measure CD4:CD8 ratio. We identified two regions of strong association. The first was located in the major histocompatibility complex (MHC), with multiple SNPs strongly associated with CD4:CD8 ratio (rs2524054, p = 2.1 × 10−28). The second region was centered within a cluster of genes from the Schlafen family and was associated with NK cell levels (rs1838149, p = 6.1 × 10−14). The MHC association with CD4:CD8 replicated convincingly (p = 1.4 × 10−9) in an independent panel of 988 individuals. Conditional analyses indicate that there are two major independent quantitative trait loci (QTL) in the MHC region that regulate CD4:CD8 ratio: one is located in the class I cluster and influences CD8 levels, whereas the second is located in the class II cluster and regulates CD4 levels. Jointly, both QTL explained 8% of the variance in CD4:CD8 ratio. The class I variants are also strongly associated with durable host control of HIV, and class II variants are associated with type-1 diabetes, suggesting that genetic variation at the MHC may predispose one to immune-related diseases partly through disregulation of T cell homeostasis.
Resumo:
Inflammatory bowel disease (IBD) describes a group of chronic relapsing inflammatory conditions of the gastrointestinal tract (GIT), with Crohn’s disease and ulcerative colitis being the two most common. Ulcerative colitis affects the colon, with the inflammation limited to the colonic mucosal layers. In contrast, the full thickness of the gut wall can be inflamed in Crohn’s disease, and any part of the GIT can be affected – from the mouth to the anus, though the small and large intestine are most commonly involved...
Resumo:
Food poisoning is used to describe a range of illnesses caused by drinking or eating contaminated drink or food. Infectious pathogens include bacteria, viruses, parasites, or their toxins, though food poisoning can also be a result of eating poisonous plants e.g. some mushrooms, or animals e.g. puffer fish. Common symptoms include nausea, vomiting, watery diarrhoea, abdominal pain and cramps, and fevers, though these will vary depending on the causative pathogen or toxin. Symptoms can start within hours of eating contaminated food, or may begin days or weeks later. Most food poisoning is mild in nature, lasts for several hours to a few days, and generally resolves without treatment. However, some cases of food poisoning can also be extremely severe, with people requiring medical attention or admission to hospital...
Resumo:
We have all made these New Year’s resolutions before ... to be healthier, to eat better, to look after ourselves more, to go to the gym more. Each year, we are adamant we will stick with these resolutions, but deep down, we all know most of us will have given up before February even arrives. So we have put together a few tips to help you actively support your customers to make a significant lifestyle change for the New Year. Healthy eating – it is important for your customers to have realistic expectations. It is all too easy to say they will stop eating junk food, and start ‘eating healthy’. Advising them that it is important to be realistic and starting with a few small measurable goals, such as aiming to eat two servings of fruits or five servings of vegetables each day, will work better in the long run. Small tweaks and modifications can add up to a major change quite quickly...
Resumo:
“We wish you a Merry Christmas, and a Happy New Year” ... when the Christmas carols start playing in the pharmacy, it is a reminder the silly season has crept up on us. Christmas should be a time of celebration, fun and spending time with loved ones and families. However, if pharmacies are not prepared it can easily turn into the “nightmare before Christmas”. So to make sure everything runs smoothly like Santa’s schedule, we have compiled a few tips to help retailers survive and prepare for Christmas...