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1.
Angew Chem Int Ed Engl ; 62(49): e202309498, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-37786992

RESUMO

Here, we show the conversion of unactivated alkenes into α-branched enones via regioselective chloroacylation with acyl chlorides. The method relies upon the initial in situ generation of chlorine radicals directly from the acyl chloride precursor under cooperative nickel/photoredox catalysis. Subsequent HCl elimination provides enones and α,ß-unsaturated esters that are not accessible via the conventional acylation approaches that provide the other, linear constitutional isomer.

2.
EMBO J ; 42(10): e111806, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-36988334

RESUMO

Spatially organized reaction dynamics between proto-oncogenic epidermal growth factor receptor (EGFR) and protein tyrosine phosphatases determine EGFR phosphorylation dynamics in response to growth factors and thereby cellular behavior within developing tissues. We show that the reaction dynamics of mutual inhibition between RPTPγ phosphatase and autocatalytic ligandless EGFR phosphorylation enable highly sensitive promigratory EGFR signaling responses to subnanomolar EGF levels, when < 5% receptors are occupied by EGF. EGF thereby triggers an autocatalytic phospho-EGFR reaction by the initial production of small amounts of phospho-EGFR through transient, asymmetric EGF-EGFR2 dimers. Single cell RPTPγ oxidation imaging revealed that phospho-EGFR induces activation of NADPH oxidase, which in turn inhibits RPTPγ-mediated dephosphorylation of EGFR, tilting the autocatalytic RPTPγ/EGFR toggle switch reaction towards ligandless phosphorylated EGFR. Reversibility of this reaction to EGF is maintained by the constitutive phosphatase activity of endoplasmic reticulum-associated TCPTP. This RPTPγ/EGFR reaction at the plasma membrane causes promigratory signaling that is separated from proliferative signaling induced by accumulated, liganded, phosphorylated EGF-EGFR in endosomes. Accordingly, loss of RPTPγ results in constitutive promigratory signaling from phosphorylated EGFR monomers. RPTPγ is thus a suppressor of promigratory oncogenic but not of proliferative EGFR signaling.


Assuntos
Fator de Crescimento Epidérmico , Proteínas Tirosina Fosfatases Classe 5 Semelhantes a Receptores , Fator de Crescimento Epidérmico/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Proteínas Tirosina Fosfatases Classe 5 Semelhantes a Receptores/metabolismo , Receptores ErbB/metabolismo , Transdução de Sinais , Fosforilação , Oxirredução
3.
Trials ; 24(1): 76, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36726155

RESUMO

BACKGROUND: Incisional hernia is a frequent complication following loop ileostomy reversal. Incisional hernias are associated with morbidity, loss of health-related quality of life and costs and warrant the investigation of prophylactic measures. Prophylactic mesh implantation at the time of surgical stoma reversal has shown to be a promising and safe method to prevent incisional hernias in this setting. However, the efficacy of this method has not yet been investigated in a large multicentre randomised-controlled trial (RCT) with adequate external validity. The P.E.L.I.O.N. trial will evaluate the efficacy of prophylactic mesh reinforcement after loop ileostomy closure in decreasing the rate of incisional hernia versus standard closure alone. METHODS: P.E.L.I.O.N. is a multicentre, patient- and observer-blind RCT. Patients undergoing loop ileostomy closure will undergo intraoperative 1:1 randomisation into either abdominal wall closure with a continuous slowly absorbable suture in small-stitch technique without mesh reinforcement (control group) or abdominal wall closure with an additional reinforcement with a retromuscular non-absorbable, macro-pore (pore size ≥ 1000 µm or effective porosity >0%) light-weight monofilament or mixed structure mesh. A total of 304 patients (152 per group) will need to be randomised in the study. Based on inclusion and exclusion criteria, 1,014 patients are expected to be screened for eligibility in order to recruit the necessary number of patients. The primary endpoint will be the frequency of incision hernias within 24 months according to the European Hernia Society definition. Secondary endpoints will be the frequency of surgical site occurrences (including surgical site infections, wound seromas and hematomas, and enterocutaneous fistulas), postoperative pain, the number of revision surgeries and health-related quality of life. Safety will be assessed by measuring postoperative complications ≥ grade 3 according to the Dindo-Clavien classification. DISCUSSION: Depending on the results of the P.E.L.I.O.N. trial, prophylactic mesh implantation could become the new standard for loop ileostomy reversal. TRIAL REGISTRATION: DRKS00027921, U1111-1273-4657.


Assuntos
Técnicas de Fechamento de Ferimentos Abdominais , Hérnia Incisional , Estomas Cirúrgicos , Humanos , Hérnia Incisional/etiologia , Hérnia Incisional/prevenção & controle , Ileostomia/efeitos adversos , Telas Cirúrgicas/efeitos adversos , Incidência , Técnicas de Fechamento de Ferimentos Abdominais/efeitos adversos
4.
Chem Commun (Camb) ; 58(77): 10809-10812, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36069397

RESUMO

Pd-catalyzed alkenylations of metallocenes via C-H activation were developed using electronically tunable pyrazolonaphthyridine (PzNPy) ligands. Ferrocene was alkenylated using the most electron-deficient ligand in the series, whereas the less reactive ruthenocene needed balancing of the electrophilicity and stability of catalysts. Various alkenes were installed, allowing fine-tuning of redox potentials.


Assuntos
Alcenos , Paládio , Compostos Ferrosos , Ligantes , Metalocenos , Compostos Organometálicos
5.
Sci Rep ; 11(1): 14802, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34285304

RESUMO

A key challenge to advance the efficiency of bioprocesses is the uncoupling of biomass from product formation, as biomass represents a by-product that is in most cases difficult to recycle efficiently. Using the example of rhamnolipid biosurfactants, a temperature-sensitive heterologous production system under translation control of a fourU RNA thermometer from Salmonella was established to allow separating phases of preferred growth from product formation. Rhamnolipids as bulk chemicals represent a model system for future processes of industrial biotechnology and are therefore tied to the efficiency requirements in competition with the chemical industry. Experimental data confirms function of the RNA thermometer and suggests a major effect of temperature on specific rhamnolipid production rates with an increase of the average production rate by a factor of 11 between 25 and 38 °C, while the major part of this increase is attributable to the regulatory effect of the RNA thermometer rather than an unspecific overall increase in bacterial metabolism. The production capacity of the developed temperature sensitive-system was evaluated in a simple batch process driven by a temperature switch. Product formation was evaluated by efficiency parameters and yields, confirming increased product formation rates and product-per-biomass yields compared to a high titer heterologous rhamnolipid production process from literature.


Assuntos
Glicolipídeos/metabolismo , RNA Bacteriano/metabolismo , Salmonella/crescimento & desenvolvimento , Biotecnologia , Engenharia Metabólica , Modelos Moleculares , Conformação Molecular , RNA Bacteriano/química , Salmonella/genética , Salmonella/metabolismo , Temperatura , Termômetros
6.
AMB Express ; 9(1): 154, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31555921

RESUMO

The microbial production of rhamnolipids has been in the focus of research for the last decades. Today, mainly heterologous production systems are targeted due to the advantage of non-pathogenic hosts as well as uncoupling from complex quorum sensing regulatory networks compared to their natural producer Pseudomonas aeruginosa. In the recent past, the presence and function of a ROSE-like RNA-thermometer located in the 5'UTR of the rhamnosyltransferase genes rhlAB has been reported in wild type P. aeruginosa. In this study, the temperature-induced regulation of this native RNA-thermometer for heterologous rhamnolipid production was evaluated and its potential application for process control is discussed. For this purpose, the non-pathogenic production host P. putida KT2440 containing the rhlAB genes with the native P. aeruginosa 5'-UTR region was used. The system was evaluated and characterized regarding the effect of temperature on growth and product formation, as represented by efficiency parameters and yields. Experimental data suggests a major effect of temperature on specific rhamnolipid production rates. With maximum values of 0.23 g/(g h) at 37 °C, this constitutes a more than 60% increase compared to the production rate of 0.14 g/(g h) at the growth optimum of 30 °C. Interestingly however, control experiments unveiled that besides the regulatory effect of the RNA-thermometer, multiple metabolic effects may contribute equally to the observed increase in production rate. As such, this work constitutes an important step towards the utilization of temperature-based process designs and enables the possibility for novel approaches for process control.

7.
BMC Med Educ ; 18(1): 85, 2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29716611

RESUMO

BACKGROUND: Evaluation of two different self-educational methods (video assisted learning versus video assisted learning plus a nodal point operation primer) on learning laparoscopic suturing and intracorporal knotting. METHODS: Randomized controlled trial at the laparoscopic surgical training center, University of Tubingen with 45 surgical novices first year medical students being pretested for dexterity. After self-educational training for 90 min with either method (Group A: video assisted learning, Group B: video assisted learning plus a nodal point operation primer) participants had to perform five laparoscopic intracorporal knots. Assessed were number of knots completed (maximum of five knots counted, knot integrity, technical proficiency and knotting time per knot. Primary outcome measure is a composed knot score combining knot integrity, technical proficiency and knotting time. RESULTS: Group B (n = 23) achieved a significantly higher composed knot score than Group A (n = 22) (53.3 ± 8.4 versus 46.5 ± 13.6 points respectively, p = 0.016). Median knotting time per completed knot was significantly different between Group B and Group A (308 s [100-1221] versus 394 s [138-1397] respectively, p = 0.001). Concerning number of completed knots there was a trend towards more knots achieved in Group B (4.2 ± 1.2 versus 3.55 ± 1.4 respectively, p = 0.075) . CONCLUSIONS: The use of a nodal point operation primer highlighting essential key steps of a procedure augment the success of learning laparoscopic skills as suturing and intracorporal knotting. (UIN researchregistry3866, March 22, 2018).


Assuntos
Recursos Audiovisuais , Laparoscopia/educação , Destreza Motora , Autoaprendizagem como Assunto , Estudantes de Medicina , Técnicas de Sutura/educação , Adulto , Competência Clínica , Feminino , Humanos , Masculino , Avaliação de Programas e Projetos de Saúde , Fatores de Tempo , Adulto Jovem
8.
Int J Surg ; 55: 46-50, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29777882

RESUMO

BACKGROUND: Hypocalcemia after total thyroidectomy is the most frequent complication resulting in prolongation of hospitalisation. Therefore we aimed to analyse clinical risk factors predictive for hypocalcemia and its long term persistence after total thyroidectomy. METHODS: Retrospective analysis of patients undergoing total thyroidectomy from 2005 until 2013. Outcome measures were initial postoperative hypocalcemia defined as serum calcium below 2.0 mmol/l after total thyroidectomy within 48 h and persistent hypocalcemia defined as serum calcium below 2.0 mmol/l above six months and/or the need for additional calcium and vitamin D supplementation. RESULTS: Initial postoperative hypocalcemia was present in 160 of 702 patients (22.8%) with 91 patients (13%) developing symptoms. 48 patients (6.8%) had a persistent hypocalcemia above six months. Patients with an initial symptomatic postoperative hypocalcemia showed significantly more often a persistent hypocalcemia compared to asymptomatic patients with biochemical hypocalcemia (38 patients (41.8%) vs. 10 patients (14.5%), p < 0,001). In the binary logistic regression analysis, female gender (OR 2.4; CI95% 1.5-3.8), prolonged surgery time >189 min (OR 1.8; CI95% 1.2-2.6) and parathyroid reimplantation (OR 2.4; CI95% 1.2-4.7) were associated with initial hypocalcemia while only initial symptomatic hypocalcaemia was shown to be independently associated with persistent hypocalcemia (OR 40.9; CI95% 18.5-90.4). CONCLUSION: Prolonged surgery time seems to correlate with initial postoperative hypocalcemia independently of the underlying disease and surgical expertise but does not affect the persistence of hypocalcemia. Initial symptomatic postoperative hypocalcemia after total thyroidectomy is associated with a high rate of persistent hypocalcemia.


Assuntos
Hipocalcemia/etiologia , Complicações Pós-Operatórias/etiologia , Tireoidectomia/efeitos adversos , Adulto , Idoso , Cálcio/sangue , Cálcio/uso terapêutico , Suplementos Nutricionais , Feminino , Humanos , Hipocalcemia/terapia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Glândulas Paratireoides/cirurgia , Hormônio Paratireóideo/sangue , Complicações Pós-Operatórias/terapia , Período Pós-Operatório , Estudos Retrospectivos , Fatores de Risco , Fatores Sexuais , Vitamina D/uso terapêutico , Vitaminas/uso terapêutico
9.
Int J Surg Case Rep ; 37: 36-40, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28633125

RESUMO

BACKGROUND: Primary squamous cell cancer (PSCC) of thyroid is a rare malignancy with poor prognosis. It is mandatory to exclude secondary involvement of the thyroid by panendoscopy, CT-scan and immunohistochemical analysis. As treatment surgery, radiation and rarely chemotherapy is employed. METHODS: A systematic review of the literature was conducted searching medline and embase database using the medical subject headings "primary squamous cell carcinoma of thyroid" and "primary squamous cell cancer of thyroid", for articles published until April 2016 (n=1733). Of interest were the used treatment modalities and survival outcomes. RESULTS: A total of 35 publications reporting on 50 cases including ours were finally analyzed. A curative treatment approach was described in 24 patients (48%). Additional radiotherapy, chemotherapy or radiochemotherapy was applied in 17, 7 and 7 patients respectively. Median overall survival was 6 months [range 0-48] for 47 patients. Disease free survival was only achieved in 8 patients with disease limited to the thyroid gland, complete surgical resection and additional radiotherapy or radiochemotherapy [reported median 20 months; range 12-48]. CONCLUSION: Reported disease free survival of PSCC of the thyroid was only achieved in patients with complete surgical resection in combination with adjuvant radio- and/or chemotherapy. However long term survival has not been reported in the literature yet.

10.
J Neurooncol ; 130(3): 439-448, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27619981

RESUMO

Tissue inhibitor of metalloproteinases-1 (TIMP-1) has been associated with poor prognosis and resistance towards chemotherapy in several cancer forms. In a previous study we found an association between a low TIMP-1 tumor immunoreactivity and increased survival for glioblastoma patients, when compared to moderate and high TIMP-1 tumor immunoreactivity. The aim of the present study was to further evaluate TIMP-1 as a biomarker in gliomas by studying TIMP-1 gene copy numbers by fluorescence in situ hybridization (FISH) on 33 glioblastoma biopsies and by measuring levels of TIMP-1 in plasma obtained pre-operatively from 43 patients (31 gliomas including 21 glioblastomas) by enzyme-linked immunosorbent assay (ELISA). The results showed TIMP-1 gene copy numbers per cell ranging from 1 to 5 and the TIMP-1/CEN-X ratio ranging between 0.7 and 1.09, suggesting neither amplification nor loss of the TIMP-1 gene. The TIMP-1 protein levels measured in plasma were not significantly higher than TIMP-1 levels measured in healthy subjects. No correlation was identified between TIMP-1 tumor cell immunoreactivities and the TIMP-1 gene copy numbers or the plasma TIMP-1 levels. In conclusion, high immunohistochemical TIMP-1 protein levels in glioblastomas were not caused by TIMP-1 gene amplification and TIMP-1 in plasma was low and not directly related to tumor TIMP-1 immunoreactivity. The study suggests that TIMP-1 immunohistochemistry is the method of choice for future clinical studies evaluating TIMP-1 as a biomarker in glioblastomas.


Assuntos
Neoplasias Encefálicas/sangue , Neoplasias Encefálicas/genética , Glioblastoma/sangue , Glioblastoma/genética , Inibidor Tecidual de Metaloproteinase-1/sangue , Inibidor Tecidual de Metaloproteinase-1/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Variações do Número de Cópias de DNA , Dinamarca , Feminino , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade , Análise Serial de Tecidos
11.
World J Surg ; 40(12): 2888-2891, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27431317

RESUMO

BACKGROUND: Clinical pathways aim to standardize perioperative and postoperative care of surgical procedures and are shown to result in a significant optimization associated with cost reduction. The aim of this study was to establish the impact of two different implementations forms of clinical pathways on the pathway compliance and resulting costs. METHODS: Data of patients undergoing elective cholecystectomy for symptomatic cholecystolithiasis were collected over two different periods: using a clinical pathway in the form of a paper-based checklist, or a clinical pathway integrated into the paper-based medical treatment and nursing documentation. Outcome measures were compliance of the clinical pathway and total costs per case. RESULTS: The compliance was significantly higher using integrated pathways compared to paper-based checklists (n = 117 of 123, 95 % vs 54 of 118, 46 %; p < 0.001). Mean total costs (€2206 vs €2458, p = 0.027) and length of hospital stay (2.13 vs 2.77 days, p < 0.001) were significantly reduced by the integrated clinical pathway compared to checklists. Further, the variation of costs per case and variation of length of hospital stay were significantly smaller with integrated clinical pathway (±€440 vs ±€538, p = 0.039 and ±0.53 vs ±0.68 days, p < 0.001, respectively). No difference regarding postoperative complication was observed (n = 3 vs. 4 events; p = 0.67). CONCLUSION: Integrated clinical pathways display a significant higher compliance compared to checklists resulting in reduced total costs, shorter hospital stay and a smaller variation of cost, making it a useful tool in process controlling and planning.


Assuntos
Colecistectomia Laparoscópica , Procedimentos Clínicos , Procedimentos Cirúrgicos Eletivos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Adulto Jovem
13.
World J Surg Oncol ; 13: 338, 2015 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-26684213

RESUMO

BACKGROUND: Rapid growth of thyroid nodules is described as being associated with thyroid cancer. The objective of the study was to determine how the growth rate of thyroid nodules during follow-up is associated with the risk of thyroid cancer. METHODS: Retrospective analysis of patients undergoing thyroid surgery for nodular disease and a repetitive preoperative ultrasound work-up of at least 6 months was done. Nodule growth was considered relevant when a volume increase >49% was detected. Growth patterns were described as rapid for a volume increase present over 6 to 24 months. RESULTS: Of the 297 analysed patients, 226 (76%) displayed relevant nodule growth and 71 (24%) no relevant growth. A rapid growth pattern was seen in 73 patients (32%). Well-differentiated thyroid cancer was diagnosed in 33 patients (11%; 27 papillary, 6 follicular) with a relevant nodule growth in 2 and no relevant growth in 31 patients. No rapid growth pattern was observed in any case of well-differentiated thyroid cancer. A rapid growth pattern occurred only in benign nodules (70 patients) and in 1 patient each with a lymphoma, a metastasis of a renal cell cancer and a metastasis of a gastric adenocarcinoma. Therapy with levothyroxine and/or iodine was administered to 129 patients (43%) and was significantly inversely correlated with nodule growth (odds ratio 0.27; CI 95 % 0.14-0.53, p < 0.001). CONCLUSIONS: Thyroid nodule growth alone and especially a rapid growth pattern during follow-up for thyroid nodular disease is not a marker for well-differentiated thyroid cancer and should not be used as a stand-alone argument for thyroid surgery.


Assuntos
Adenocarcinoma Folicular/secundário , Adenocarcinoma/secundário , Carcinoma Papilar/secundário , Diferenciação Celular , Neoplasias da Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/patologia , Adenocarcinoma/cirurgia , Adenocarcinoma Folicular/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Papilar/cirurgia , Feminino , Seguimentos , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/cirurgia , Nódulo da Glândula Tireoide/cirurgia , Adulto Jovem
14.
Emerg Med J ; 32(9): 698-702, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25476715

RESUMO

BACKGROUND: Hyperbilirubinaemia is reported to be a positive predictor in diagnosing appendicitis and especially appendiceal perforation. We, therefore, analysed the diagnostic accuracy of serum bilirubin in anticipating appendicitis and its severity. METHODS: All consecutive patients undergoing appendectomy for suspected appendicitis from May 2009 to August 2011 were analysed. Patients were classified based on final histopathological findings into the groups: no appendiceal inflammation, non-perforated appendicitis and perforated appendicitis. Primary outcome was the diagnostic accuracy of serum bilirubin levels in discriminating between no appendiceal inflammation and any appendicitis (perforated and non-perforated appendicitis) and non-perforated and perforated appendicitis. RESULTS: Of 493 analysed patients, 125 (25%) had no appendiceal inflammation, 312 (64%) had non-perforated appendicitis and 56 (11%) had perforated appendicitis. The proportion of patients with bilirubin elevation (>1.1 mg/dL) was different between those with no appendiceal inflammation (14%) and any appendicitis (36%) (p<0.0001), and between non-perforated appendicitis and perforated appendicitis 48% (p=0.04). However, the positive and negative likelihood ratios (LRs) for an elevated bilirubin were poor at discriminating the groups: no appendiceal inflammation versus any appendicitis (LR+ 2.62 (95% CI 1.65 to 4.16) and LR- 0.75 (95% CI 0.67 to 0.83)) and non-perforated appendicitis versus perforated appendicitis (LR+ estimate 1.74 (95% CI 1.28 to 2.38) and LR- 0.72 (95% CI 0.55 to 0.93)). CONCLUSIONS: Hyperbilirubinaemia is present in acute appendicitis but has a low diagnostic accuracy in discriminating between any appendicitis versus no appendiceal inflammation and perforated versus non-perforated appendicitis and is, therefore, of limited value in clinical routine. TRIAL REGISTRATION NUMBER: NCT01698099.


Assuntos
Apendicite/sangue , Apendicite/patologia , Bilirrubina/sangue , Hiperbilirrubinemia/complicações , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Apendicectomia , Apendicite/cirurgia , Feminino , Humanos , Hiperbilirrubinemia/diagnóstico , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Curva ROC , Estudos Retrospectivos , Adulto Jovem
15.
Nanotechnology ; 25(11): 115303, 2014 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-24561614

RESUMO

Low energy ion beam pattern formation on Si with simultaneous co-deposition of Ag, Pd, Pb, Ir, Fe or C impurities was investigated by in situ scanning tunneling microscopy as well as ex situ atomic force microscopy, scanning electron microscopy, transmission electron microscopy and Rutherford backscattering spectrometry. The impurities were supplied by sputter deposition. Additional insight into the mechanism of pattern formation was obtained by more controlled supply through e-beam evaporation. For the situations investigated, the ability of the impurity to react with Si, i.e. to form a silicide, appears to be a necessary, but not a sufficient condition for pattern formation. Comparing the effects of impurities with similar mass and nuclear charge, the collision kinetics is shown to be not of primary importance for pattern formation. To understand the observed phenomena, it is necessary to assume a bi-directional coupling of composition and height fluctuations. This coupling gives rise to a sensitive dependence of the final morphology on the conditions of impurity supply. Because of this history dependence, the final morphology cannot be uniquely characterized by a steady state impurity concentration.

16.
IEEE Trans Biomed Eng ; 61(2): 381-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23996534

RESUMO

The experimental verification of a novel sensor topology capable of measuring both the position and energy of an electron beam inside a compact electron linear accelerator for radiotherapy is presented. The method applies microwave sensing techniques and allows for the noninterceptive monitoring of the respective beam parameters within compact accelerators for medical or industrial purposes. A state space feedback approach is described with the help of which beam displacements, once detected, can be corrected within a few system macropulses. The proof-of-principle experiments have been conducted with a prototype accelerator and customized hardware. Additionally, closed-loop operation with high accuracy is demonstrated.


Assuntos
Modelos Teóricos , Aceleradores de Partículas/instrumentação , Radioterapia/instrumentação , Desenho de Equipamento , Retroalimentação
17.
BMC Cancer ; 13: 489, 2013 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-24144331

RESUMO

BACKGROUND: Platinum-based chemotherapy has long been used in the treatment of a variety of cancers and functions by inducing DNA damage. ERCC1 and ERCC4 are involved in the removal of this damage and have previously been implicated in resistance to platinum compounds. The aim of the current investigation is to determine the presence, frequency and prognostic impact of ERCC1 or ERCC4 gene copy number alterations in colorectal cancer (CRC). METHODS: Fluorescent in situ hybridization probes directed at ERCC1 and ERCC4 with relevant reference probes were constructed. Probes were tested in a CRC cell line panel and in tumor sections from 152 stage III CRC chemonaive patients. Relationships between biomarker status and clinical endpoints (overall survival, time to recurrence, and local recurrence in rectal cancer) were analyzed by survival statistics. RESULTS: ERCC1-19q13 copy number alterations were observed in a single cell line metaphase (HT29). In patient material, ERCC1-19q13 copy number gains (ERCC1-19q13/CEN-2 ≥ 1.5) were detected in 27.0% of specimens, whereas ERCC1-19q13 deletions (ERCC1-19q13/CEN-2 < 0.8) were only detected in 1.3%. ERCC1-19q13 gain was significantly associated with longer survival (multivariate analysis, HR: 0.45, 95% CI: 0.20-1.00, p = 0.049) in patients with colon tumors, but not rectal tumors. No ERCC4 aberrations were detected and scoring was discontinued after 50 patients. CONCLUSIONS: ERCC1-19q13 copy number gains occur frequently in stage III CRC and influences survival in patients with colon tumors. Future studies will investigate the effect of ERCC1-19q13 aberrations in a platinum-treated patient population with the aim of developing a predictive biomarker profile for oxaliplatin sensitivity in CRC.


Assuntos
Cromossomos Humanos Par 19 , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Variações do Número de Cópias de DNA , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Fatores Etários , Linhagem Celular Tumoral , Aberrações Cromossômicas , Estudos de Coortes , Neoplasias Colorretais/mortalidade , Feminino , Humanos , Hibridização in Situ Fluorescente , Masculino , Estadiamento de Neoplasias , Avaliação de Resultados da Assistência ao Paciente , Fatores Sexuais
18.
PLoS One ; 8(4): e60613, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23577133

RESUMO

BACKGROUND: Topoisomerase I (Top1) is the target of Top1 inhibitor chemotherapy. The TOP1 gene, located at 20q12-q13.1, is frequently detected at elevated copy numbers in colorectal cancer (CRC). The present study explores the mechanism, frequency and prognostic impact of TOP1 gene aberrations in stage III CRC and how these can be detected by fluorescent in situ hybridization (FISH). METHODS: Nine CRC cell line metaphase spreads were analyzed by FISH with a TOP1 probe in combination with a reference probe covering either the centromeric region of chromosome 20 (CEN-20) or chromosome 2 (CEN-2). Tissue sections from 154 chemonaive stage III CRC patients, previously studied with TOP1/CEN-20, were analyzed with TOP1/CEN-2. Relationships between biomarker status and overall survival (OS), time to recurrence (TTR) in CRC and time to local recurrence (LR; rectal cancer only) were determined. RESULTS: TOP1 aberrations were observed in four cell line metaphases. In all cell lines CEN-2 was found to reflect chromosomal ploidy levels and therefore the TOP1/CEN-2 probe combination was selected to identify TOP1 gene gains (TOP1/CEN-2≥1.5). One hundred and three patients (68.2%) had TOP1 gain, of which 15 patients (14.6%) harbored an amplification (TOP1/CEN-20≥2.0). TOP1 gene gain did not have any association with clinical endpoints, whereas TOP1 amplification showed a non-significant trend towards longer TTR (multivariate HR: 0.50, p = 0.08). Once amplified cases were segregated from other cases of gene gain, non-amplified gene increases (TOP1/CEN-2≥1.5 and TOP1/CEN-20<2.0) showed a trend towards shorter TTR (univariate HR: 1.57, p = 0.07). CONCLUSIONS: TOP1 gene copy number increase occurs frequently in stage III CRC in a mechanism that often includes CEN-20. Using CEN-2 as a measurement for tumor ploidy levels, we were able to discriminate between different mechanisms of gene gain, which appeared to differ in prognostic impact. TOP1 FISH guidelines have been updated.


Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , DNA Topoisomerases Tipo I/genética , Dosagem de Genes/genética , Linhagem Celular Tumoral , Cromossomos Humanos Par 2/genética , Cromossomos Humanos Par 20/genética , Estudos de Coortes , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/enzimologia , Feminino , Humanos , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico
19.
Clin Cancer Res ; 19(5): 1281-9, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23340303

RESUMO

PURPOSE: Clinically validated biomarkers for anti-angiogenesis agents are not available. We have previously reported associations between candidate VEGFA single-nucleotide polymorphisms (SNP) and overall survival (OS) in E2100. The associations between tumor VEGFA amplification and outcome are evaluated here. EXPERIMENTAL DESIGN: E2100 was a phase III trial comparing paclitaxel with or without bevacizumab for patients with metastatic breast cancer. FISH to assess gene amplification status for VEGFA was conducted on paraffin-embedded tumors from 363 patients in E2100. Evaluation for association between amplification status and outcomes was conducted. RESULTS: Estrogen receptor (ER)+ or progesterone receptor (PR)+ tumors were less likely to have VEGFA amplification than ER/PR- tumors (P = 0.020). VEGFA amplification was associated with worse OS (20.2 vs. 25.3 months; P = 0.013) in univariate analysis with a trend for worse OS in multivariate analysis (P = 0.08). There was a significant interaction between VEGFA amplification, hormone receptor status, and study arm. Patients with VEGFA amplification and triple-negative breast cancers (TNBC) or HER2 amplification had inferior OS (P = 0.047); amplification did not affect OS for those who were ER+ or PR+ and HER2-. Those who received bevacizumab with VEGFA amplification had inferior progression-free survival (PFS; P = 0.010) and OS (P = 0.042); no association was seen in the control arm. Test for interaction between study arm and VEGFA amplification with OS was not significant. CONCLUSION: VEGFA amplification in univariate analysis was associated with poor outcomes; this was particularly prominent in HER2+ or TNBCs. Additional studies are necessary to confirm the trend for poor OS seen on multivariate analysis for patients treated with bevacizumab.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Amplificação de Genes , Fator A de Crescimento do Endotélio Vascular/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/administração & dosagem , Bevacizumab , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Feminino , Seguimentos , Humanos , Hibridização in Situ Fluorescente , Pessoa de Meia-Idade , Metástase Neoplásica , Estadiamento de Neoplasias , Paclitaxel/administração & dosagem , Prognóstico , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Estudos Retrospectivos , Taxa de Sobrevida , Análise Serial de Tecidos
20.
Mol Oncol ; 7(1): 101-11, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23110915

RESUMO

PURPOSE: A Topoisomerase 1 (Top1) poison is frequently included in the treatment regimens for metastatic colorectal cancer (mCRC). However, no predictive biomarkers for Top1 poisons are available. We here report a study on the TOP1 gene copy number in CRC patients and its association with patient prognosis and tumor cell proliferation. EXPERIMENTAL DESIGN: The study included TOP1 and CEN-20 fluorescence in situ hybridization (FISH) analyses on formalin fixed paraffin embedded (FFPE) tissue sections from 154 stage III CRC chemonaïve patients. The frequencies of aberration in the TOP1 gene copy number, the CEN-20 copy number and the TOP1/CEN-20 ratio were analyzed and associated with overall survival (OS), time to recurrence (TTR) and in a subgroup analysis of rectal cancer patients only with time to local recurrence (LR in RC). Moreover, the TOP1 and CEN-20 copy numbers were correlated with the tumor Ki67 proliferation index. RESULTS: 35.7% of the tumors had an increased TOP1 copy number above 4n gene copies per cell and 28.6% and 9.7% had a TOP1/CEN-20 ratio ≥1.5 or ≥2.0, respectively. The TOP1 copy number and the TOP1/CEN-20 ratios were separately added into multivariate analyses as continuous variables, in which also age, gender, primary tumor location and Ki67 status were added as covariates. In contrast to the TOP1/CEN-20 ratio, the TOP1 copy number was significantly associated with OS (HR: 0.62; 95% CI: 0.42-0.90; p = 0.01). Neither the TOP1 copy number nor the ratio was significantly associated with TTR and only the TOP1/CEN-20 ratio was significantly associated with LR in RC (HR: 0.25; 95% CI: 0.08-0.83; p = 0.02). No significant correlation was found between the TOP1 copy number and proliferation, while a weak and inverse correlation between the CEN-20 copy number and proliferation was observed. CONCLUSIONS: This study showed that increased TOP1 gene copy numbers are frequent findings in cancer cells in stage III CRC tumors but unrelated to the proliferative status of the tumors. The association with prognosis is important to consider when planning and analyzing future studies investigating TOP1 as a potential predictive biomarker for Top1 poisons.


Assuntos
Neoplasias Colorretais/genética , DNA Topoisomerases Tipo I/genética , Dosagem de Genes/genética , Humanos , Hibridização In Situ , Prognóstico
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