897 resultados para TARGETED DISRUPTION
Resumo:
The advent of multiparametric MRI has made it possible to change the way in which prostate biopsy is done, allowing to direct biopsies to suspicious lesions rather than randomly. The subject of this review relates to a computer-assisted strategy, the MRI/US fusion software-based targeted biopsy, and to its performance compared to the other sampling methods. Different devices with different methods to register MR images to live TRUS are currently in use to allow software-based targeted biopsy. Main clinical indications of MRI/US fusion software-based targeted biopsy are re-biopsy in men with persistent suspicious of prostate cancer after first negative standard biopsy and the follow-up of patients under active surveillance. Some studies have compared MRI/US fusion software-based targeted versus standard biopsy. In men at risk with MRI-suspicious lesion, targeted biopsy consistently detects more men with clinically significant disease as compared to standard biopsy; some studies have also shown decreased detection of insignificant disease. Only two studies directly compared MRI/US fusion software-based targeted biopsy with MRI/US fusion visual targeted biopsy, and the diagnostic ability seems to be in favor of the software approach. To date, no study comparing software-based targeted biopsy against in-bore MRI biopsy is available. The new software-based targeted approach seems to have the characteristics to be added in the standard pathway for achieving accurate risk stratification. Once reproducibility and cost-effectiveness will be verified, the actual issue will be to determine whether MRI/TRUS fusion software-based targeted biopsy represents anadd-on test or a replacement to standard TRUS biopsy.
Resumo:
Notch is a membrane inserted protein activated by the membrane-inserted γ-secretase proteolytic complex. The Notch pathway is a potential therapeutic target for the treatment of renal diseases but also controls the function of other cells, requiring cell-targeting of Notch antagonists. Toward selective targeting, we have developed the γ-secretase inhibitor-based prodrugs 13a and 15a as substrates for γ-glutamyltranspeptidase (γ-GT) and/or γ-glutamylcyclotransferase (γ-GCT) as well as aminopeptidase A (APA), which are overexpressed in renal diseases, and have evaluated them in experimental in vitro and in vivo models. In nondiseased mice, the cleavage product from Ac-γ-Glu-γ-secretase inhibitor prodrug 13a (γ-GT-targeting and γ-GCT-targeting) but not from Ac-α-Glu-γ-secretase inhibitor prodrug 15a (APA-targeting) accumulated in kidneys when compared to blood and liver. Potential nephroprotective effects of the γ-secretase inhibitor targeted prodrugs were investigated in vivo in a mouse model of acute kidney injury, demonstrating that the expression of Notch1 and cleaved Notch1 could be selectively down-regulated upon treatment with the Ac-γ-Glu-γ-secretase-inhibitor 13a.
Resumo:
ABSTRACT: A workshop was held at the National Institute for Diabetes and Digestive and Kidney Diseases with a focus on the impact of sleep and circadian disruption on energy balance and diabetes. The workshop identified a number of key principles for research in this area and a number of specific opportunities. Studies in this area would be facilitated by active collaboration between investigators in sleep/circadian research and investigators in metabolism/diabetes. There is a need to translate the elegant findings from basic research into improving the metabolic health of the American public. There is also a need for investigators studying the impact of sleep/circadian disruption in humans to move beyond measurements of insulin and glucose and conduct more in-depth phenotyping. There is also a need for the assessments of sleep and circadian rhythms as well as assessments for sleep-disordered breathing to be incorporated into all ongoing cohort studies related to diabetes risk. Studies in humans need to complement the elegant short-term laboratory-based human studies of simulated short sleep and shift work etc. with studies in subjects in the general population with these disorders. It is conceivable that chronic adaptations occur, and if so, the mechanisms by which they occur needs to be identified and understood. Particular areas of opportunity that are ready for translation are studies to address whether CPAP treatment of patients with pre-diabetes and obstructive sleep apnea (OSA) prevents or delays the onset of diabetes and whether temporal restricted feeding has the same impact on obesity rates in humans as it does in mice.
Resumo:
PURPOSE: Prostate cancer (PCa) diagnosis relies on clinical suspicion leading to systematic transrectal ultrasound-guided biopsy (TRUSGB). Multiparametric magnetic resonance imaging (mpMRI) allows for targeted biopsy of suspicious areas of the prostate instead of random 12-core biopsy. This method has been shown to be more accurate in detecting significant PCa. However, the precise spatial accuracy of cognitive targeting is unknown. METHODS: Consecutive patients undergoing mpMRI-targeted TRUSGB with cognitive registration (MRTB-COG) followed by robot-assisted radical prostatectomy were included in the present analysis. The regions of interest (ROIs) involved by the index lesion reported on mpMRI were subsequently targeted by two experienced urologists using the cognitive approach. The 27 ROIs were used as spatial reference. Mapping on radical prostatectomy specimen was used as reference to determine true-positive mpMRI findings. Per core correlation analysis was performed. RESULTS: Forty patients were included. Overall, 40 index lesions involving 137 ROIs (mean ROIs per index lesion 3.43) were identified on MRI. After correlating these findings with final pathology, 117 ROIs (85 %) were considered as true-positive lesions. A total of 102 biopsy cores directed toward such true-positive ROIs were available for final analysis. Cognitive targeted biopsy hit the target in 82 % of the cases (84/102). The only identified risk factor for missing the target was an anterior situated ROI (p = 0.01). CONCLUSION: In experienced hands, cognitive MRTB-COG allows for an accuracy of 82 % in hitting the correct target, given that it is a true-positive lesion. Anterior tumors are less likely to be successfully targeted.
Resumo:
To sustain a lifelong ability to initiate organs, plants retain pools of undifferentiated cells with a preserved proliferation capacity. The root pericycle represents a unique tissue with conditional meristematic activity, and its tight control determines initiation of lateral organs. Here we show that the meristematic activity of the pericycle is constrained by the interaction with the adjacent endodermis. Release of these restraints by elimination of endodermal cells by single-cell ablation triggers the pericycle to re-enter the cell cycle. We found that endodermis removal substitutes for the phytohormone auxin-dependent initiation of the pericycle meristematic activity. However, auxin is indispensable to steer the cell division plane orientation of new organ-defining divisions. We propose a dual, spatiotemporally distinct role for auxin during lateral root initiation. In the endodermis, auxin releases constraints arising from cell-to-cell interactions that compromise the pericycle meristematic activity, whereas, in the pericycle, auxin defines the orientation of the cell division plane to initiate lateral roots.
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High-resolution mass spectrometry (HRMS) has been associated with qualitative and research analysis and QQQ-MS with quantitative and routine analysis. This view is now challenged and for this reason, we have evaluated the quantitative LC-MS performance of a new high-resolution mass spectrometer (HRMS), a Q-orbitrap-MS, and compared the results obtained with a recent triple-quadrupole MS (QQQ-MS). High-resolution full-scan (HR-FS) and MS/MS acquisitions have been tested with real plasma extracts or pure standards. Limits of detection, dynamic range, mass accuracy and false positive or false negative detections have been determined or investigated with protease inhibitors, tyrosine kinase inhibitors, steroids and metanephrines. Our quantitative results show that today's available HRMS are reliable and sensitive quantitative instruments and comparable to QQQ-MS quantitative performance. Taking into account their versatility, user-friendliness and robustness, we believe that HRMS should be seen more and more as key instruments in quantitative LC-MS analyses. In this scenario, most targeted LC-HRMS analyses should be performed by HR-FS recording virtually "all" ions. In addition to absolute quantifications, HR-FS will allow the relative quantifications of hundreds of metabolites in plasma revealing individual's metabolome and exposome. This phenotyping of known metabolites should promote HRMS in clinical environment. A few other LC-HRMS analyses should be performed in single-ion-monitoring or MS/MS mode when increased sensitivity and/or detection selectivity will be necessary.
Resumo:
Gonadal somatic cell and adrenocortical endocrine tumors are rare. The incidence of adrenocortical carcinomas is only 1-2/1000000 a year. However, they are aggressive, especially in adulthood and currently surgery is the only curative treatment. Cytotoxic agents are in use in advanced cancers, but side effects and multidrug resistance are often problems. Thus there is a need for novel curative treatment methods. In contrast, ovarian granulosa cell tumors and testicular Leydig cell tumors are usually benign, especially at a younger age. The aim of the present thesis was to study a novel targeted treatment method through luteinizing hormone/chorionic gonadotropin receptor (LHCGR) in a transgenic mouse tumor model. The cytotoxic agent was lytic peptide Hecate-CGbeta conjugate where 23 amino acid Hecate, a synthetic form of honeybee venom melittin, was conjugated to 15 amino acid fragment of human chorionic gonadotropin β subunit. Lytic peptides are known to act only on negatively charged cells, such as bacteria and cancer cells and hereby, due to hCGbeta fragment, the conjugate is able to bind directly to LHCGR bearing cancer cells, saving the healthy ones. The experiments were carried out in inhibin-alpha-Simian Virus 40-T-antigen transgenic mice that are known to express LHCGR-bearing gonadal tumors, namely Leydig and granulosa cell tumors by 100% penetrance. If the mice are gonadectomized prepubertally they form adrenocortical tumors instead. Transgenic and wild type mice were treated for three consecutive weeks with control vehicle, Hecate or Hecate-CGbeta conjugate. GnRH antagonist or estradiol was given to a group of mice with or without Hecate-CGbeta conjugate to analyze the additive role of gonadotropin blockage in adrenocortical tumor treatment efficacy. Hecate-CGbeta conjugate was able to diminish the gonadal and adrenal tumor size effectively in males. No treatment related side effects were found. Gonadotropin blockage through GnRH antagonist was the best treatment in female adrenal tumors. The mode of cell death by Hecate-CGbeta conjugate was proven to be through necrosis. LHCGR and GATA-4 were co-expressed in tumors, where the treatment down-regulated their expression simultaneously, suggesting their possible use as tumor markers. In conclusion, the present thesis showed that Hecate-CGbeta conjugate targets its action selectively through LHCGR and selectively kills the LHCGR bearing tumor cells. It works both in gonadal somatic and in ectopic LHCGR bearing adrenal tumors. These results establish a more general principle that receptors expressed ectopically in malignant cells can be exploited in targeted cytotoxic therapies without affecting the normal healthy cells.
Resumo:
Helicobacter pylori (H. pylori) is a gram negative bacteria that represents a considerable global burden in the world and is related to many gastrointestinal diseases (peptic ulcer, gastric MALT lymphoma or gastric cancer). Currently the triple standard therapy is less used as there is an increase of the clarithromycin resistance. Therefore patients have to receive several lines of treatment with the consequence of adverse events and the possibility to interrupt the treatment. This is why the main objective is to determine if making a culture and antibiogram to do a targeted treatment cause less adverse events with the same eradication than making an empirical treatment to eradicate H. pylori. The secondary objective is to determine the prevalence of resistance to clarithromycin in the province of GironaThis is a multicentre clinical trial without blinding; patients are selected by non-probabilistic sampling, with a total sample of 868 patients randomized in two equal groups of 434 patients in each group. The study will last 2 years. The endpoints will be to evaluate the adverse events and eradication of each group of patients. Also it will be evaluated the resistance to clarithromycin
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Photosynthetic reactions are divided in two parts: light-driven electron transfer reactions and carbon fixation reactions. Electron transfer reactions capture solar energy and split water molecules to form reducing energy (NADPH) and energy-carrying molecules (ATP). These end-products are used for fixation of inorganic carbon dioxide into organic sugar molecules. Ferredoxin-NADP+ oxidoreductase (FNR) is an enzyme that acts at the branch point between the electron transfer reactions and reductive metabolism by catalyzing reduction of NADP+ at the last step of the electron transfer chain. In this thesis, two isoforms of FNR from A rabidopsis thaliana, FNR1 and FNR2, were characterized using the reverse genetics approach. The fnr1 and fnr2 mutant plants resembled each other in many respects. Downregulation of photosynthesis protected the single fnr mutant plants from excess formation of reactive oxygen species (ROS), even without significant upregulation of antioxidative mechanisms. Adverse growth conditions, however, resulted in phenotypic differences between fnr1 and fnr2. While fnr2 plants showed downregulation of photosynthetic complexes and upregulation of antioxidative mechanisms under low-temperature growth conditions, fnr1 plants had the wild-type phenotype, indicating that FNR2 may have a specific role in redistribution of electrons under unfavorable conditions. The heterozygotic double mutant (fnr1xfnr2) was severely devoid of chloroplastic FNR, which clearly restricted photosynthesis. The fnr1xfnr2 plants used several photoprotective mechanisms to avoid oxidative stress. In wild-type chloroplasts, both FNR isoforms were found from the stroma, the thylakoid membrane, and the inner envelope membrane. In the absence of the FNR1 isoform, FNR2 was found only in the stroma, suggesting that FNR1 and FNR2 form a dimer, by which FNR1 anchors FNR2 to the thylakoid membrane. Structural modeling predicted formation of an FNR dimer in complex with ferredoxin. In this thesis work, Tic62 was found to be the main protein that binds FNR to the thylakoid membrane, where Tic62 and FNR formed high molecular weight complexes. The formation of such complexes was shown to be regulated by the redox state of the chloroplast. The accumulation of Tic62-FNR complexes in darkness and dissociation of complexes from the membranes in light provide evidence that the complexes may have roles unrelated to photosynthesis. This and the high viability of fnr1 mutant plants lacking thylakoid-bound FNR indicate that the stromal pool of FNR is photosynthetically active.
Resumo:
The incidence of malignant melanoma of the skin has been steadily rising worldwide during the past decades. Most early detected primary tumors can be removed surgically and the prognosis is good. However, at the same time there still is no permanent cure for metastatic melanoma and its prognosis is poor, although lately new effective drugs have emerged. In this thesis, four different approaches of experimental therapy for metastatic melanoma were studied. Endogenous cis-Urocanic acid (UCA) is found in every individual’s skin, where exposure to UV light from the sun generates it from its inactive trans conformation. Cis- UCA was found to destroy malignant melanoma cells in culture under an acidified pH and sufficient concentration through caspase-3 mediated apoptosis. Furthermore, cis-UCA is able to considerably diminish the growth rate in human melanoma tumors on living SCID mice. Using replication-competent Semliki Forest viruses, human melanoma tumors grown in SCID mice were dramatically shrunken as the fulminant production of viruses in melanoma cells leads them to apoptosis within 72 hours. Small oligopeptides attaching to melanoma cells were identified using in vivo phage display. The melanoma-specific peptides found were further tested in vitro on adenoviruses. Ultimately, the adenoviral retargeting using the peptides was tested in vivo. One peptide homed to human transferring receptor upregulated on melanoma cells. In order to kill the malignant melanoma cells with the retargeted adenoviruses, the viruses should carry genetic material producing apoptotic proteins in the cancer tissue. TIMP-3 has been identified as a good candidate for such a protein, as it inhibits malignant cell adhesion as well as promotes apoptosis through a caspase-8 pathway. It is further shown here that adenovirally delivered TIMP-3 is even more potent, as it could kill non-adherent cancer cells, lacking the fully functional death receptor signalling pathway. Adenovirally delivered TIMP-2 also showed marked antitumor effects in human malignant melanoma xenografts on SCID mice both in ex vivo and systemic delivery.
Resumo:
The currently used forms of cancer therapy are associated with drug resistance and toxicity to healthy tissues. Thus, more efficient methods are needed for cancer-specific induction of growth arrest and programmed cell death, also known as apoptosis. Therapeutic forms of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) are investigated in clinical trials due to the capability of TRAIL to trigger apoptosis specifically in cancer cells by activation of cell surface death receptors. Many tumors, however, have acquired resistance to TRAIL-induced apoptosis and sensitizing drugs for combinatorial treatments are, therefore, in high demand. This study demonstrates that lignans, natural polyphenols enriched in seeds and cereal, have a remarkable sensitizing effect on TRAIL-induced cell death at non-toxic lignan concentrations. In TRAIL-resistant and androgen-dependent prostate cancer cells we observe that lignans repress receptor tyrosine kinase (RTK) activity and downregulate cell survival signaling via the Akt pathway, which leads to increased TRAIL sensitivity. A structure-activity relationship analysis reveals that the γ-butyrolactone ring of the dibenzylbutyrolactone lignans is essential for the rapidly reversible TRAIL-sensitizing activity of these compounds. Furthermore, the lignan nortrachelogenin (NTG) is identified as the most efficient of the 27 tested lignans and norlignans in sensitization of androgen-deprived prostate cancer cells to TRAIL-induced apoptosis. While this combinatorial anticancer approach may leave normal cells unharmed, several efficient cancer drugs are too toxic, insoluble or unstable to be used in systemic therapy. To enable use of such drugs and to protect normal cells from cytotoxic effects, cancer-targeted drug delivery vehicles of nanometer scale have recently been generated. The newly developed nanoparticle system that we tested in vitro for cancer cell targeting combines the efficient drug-loading capacity of mesoporous silica to the versatile particle surface functionalization of hyperbranched poly(ethylene imine), PEI. The mesoporous hybrid silica nanoparticles (MSNs) were functionalized with folic acid to promote targeted internalization by folate receptor overexpressing cancer cells. The presented results demonstrate that the developed carrier system can be employed in vitro for cancer selective delivery of adsorbed or covalently conjugated molecules and furthermore, for selective induction of apoptotic cell death in folate receptor expressing cancer cells. The tested carrier system displays potential for simultaneous delivery of several anticancer agents specifically to cancer cells also in vivo.
Resumo:
Supply chains are becoming increasingly dependent on information ex-change in today’s world, and any disruption can cause severe repercus-sions to the flow of materials in the chain. The speed, accuracy and amount of information are key factors. The aim in this thesis is to address a gap in the research by focusing on information exchange and the risks related to it in a multimodal wood supply chain operating between the Baltic States and Finland. The study involved interviewing people engaged in logistics management in the supply chain in question. The main risk the interviewees identified arose from the sea logistics system, which held a lot of different kinds of information. The threat of breakdown in the Internet connection was also found to hinder the operations significantly. A vulnerability analysis was carried out in order to identify the main actors and channels of infor-mation flow in the supply chain. The analysis revealed that the most important and therefore most vulnerable information-exchange channels were those linking the terminal superintendent, the operative managers and the mill managers. The study gives a holistic picture of the investigated supply chain. Information-exchange-related risks varied greatly. One of the most frequently mentioned was the risk of information inaccuracy, which was usually due to the fact that those in charge of the various functions did not fully understand the consequences for the entire chain.