989 resultados para varnish and PET-R


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The Cassini-Huygens arrival into the Saturnian system brought a large amount of data about the satellites and rings. Two diffuse rings were found in the region between the A ring and Prometheus. R/2004 S1 is coorbital to Atlas and R/2004 S2 is close to Prometheus. In this work we analysed the closest approach between Prometheus and both rings. As a result we found that the satellite removes particles from R/2004 S2 ring. Long-term numerical simulations showed that some particles can cross the F ring region . The well known region of the F ring, where small satellites are present and particles are being taking from the ring, gains a new insight with the presence of particles from R/2004 S2 ring. The computation of the Lyapunov Characteristic Exponent reveled that the R/2004 S2 ring lies in a chaotic region while R/2004 S1 ring and Atlas are in a stable region. Atlas is responsible for the formation of three regimes in the R/2004 S1 ring, as expected for a satellite embedded in a ring.

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Includes bibliography

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One of the aspects that influence good performance of new product development (NPD) at high-tech companies is the integration of research and development (R&D) and the other functions involved with NPD. The objective of this paper is to examine why Brazilian medium and large sized high-tech companies are different with respect to the integration of R&D with NPD. An analysis of case studies was conducted at five Brazilian high-tech firms. Among the results, collectivism, which is characteristic of the Brazilian organisational culture, was seen to manifest itself in companies through the adoption of cross-functional teams; the valorisation of personal relations, which is stimulated by physical proximity; and project managers’ ample participation in different functions involving NPD.

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Background The stimulation of acupoints along the meridians, but not the non-acupoints outside of the meridians, produces analgesia. Although the acupoint is defined at the body surface, the exact location of the acupoints is not known. This study aims to examine whether the intensity and duration of the analgesic effect of electroacupuncture (EA) at the Zusanli (ST36) and Sanynjiao acupoints (SP6) change according to the depth of the stimulation. Methods Ninety-six male Wistar rats classified as responders were arbitrarily allocated into 16 groups of six rats each. Six groups received EA with uninsulated acupuncture needles (type I) or needles that were immersed in varnish and had the varnish circularly peeled 0.2 mm from the tip (type II), 0.2 mm at 3 mm (type III) or 5 mm (type IV) from the tip, or 0.2 mm at 5 and 1 mm from the tip (type V), or EA sham for 20 min. Five groups received injection of formalin into the acupoint bilaterally at 5 mm or 1 mm deep into ST36, 5 mm below ST36 but inserting the needle at 45° to the skin surface, or 5 mm deep into non-acupoints. The remaining groups received intraplantar injection of saline, 1% or 2.5% formalin. The analgesic effects were measured by the rat tail-flick test. Results The bilateral stimulation of ST36 and SP6 by uninsulated or insulated needles produced analgesia in the rat tail-flick test. The stronger and longer lasting effects occurred after EA with the types I and V needles, or injection of formalin 5 mm deep into ST36. The remaining needles produced weaker and shorter lasting effects. Slow analgesic effect also occurred after formalin injection at 1 mm or 5 mm below ST36 by inserting the needle at 45° to the skin surface. Conclusion The experimental results suggest that the efficacy of the EA stimulation depends on the spatial distribution of the current density under the needling surface rather than only the acupoint or the depth of needling.

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Die Nuklearmedizin ist ein modernes und effektives Werkzeug zur Erkennung und Behandlung von onkologischen Erkrankungen. Molekulare Bildgebung, die auf dem Einsatz von Radiopharmaka basiert, beinhaltet die Einzel-Photonen-Emissions-Tomographie (SPECT) und Positronenemissions¬tomographie (PET) und ermöglicht die nicht-invasive Visualisierung von Tumoren auf nano-und picomolarer Ebene.rnDerzeit werden viele neue Tracer für die genauere Lokalisierung von kleinen Tumoren und Metastasen eingeführt und hinsichtlich ihrer Eignung untersucht. Die meisten von ihnen sind Protein-basierte Biomoleküle, die die Natur selbst als Antigene für die Tumorzellen produziert. Dabei spielen Antikörper und Antikörper-Fragmente eine wichtige Rolle in der Tumor-Diagnostik und Behandlung. Die PET-Bildgebung mit Antikörpern und Antikörperfragmenten bezeichnet man als immuno-PET. Ein wichtiger Aspekt hierbei ist, dass entsprechende Radiopharmaka benötigt werden, deren Halbwertszeit mit der Halbwertszeit der Biomoleküle korreliert ist.rnIn neueren Arbeiten wird 90Nb als potenzieller Kandidat für die Anwendung in der immuno-PET vorgeschlagen. Seine Halbwertszeit von 14,6 Stunden ist geeignet für die Anwendung mit Antikörperfragmenten und einige intakten Antikörpern. 90Nb hat eine relativ hohen Anteil an Positronenemission von 53% und eine optimale Energie für die β+-Emission von 0,35 MeV, die sowohl eine hohe Qualität der Bildgebung als auch eine niedrige Aktivitätsmenge des Radionuklids ermöglicht.rnErsten grundlegende Untersuchungen zeigten: i) dass 90Nb in ausreichender Menge und Reinheit durch Protonen-Bombardierung des natürlichen Zirkonium Targets produziert, ii) aus dem Targetmaterial in entsprechender radiochemischer Reinheit isoliert und iii) zur Markierung des monoklonalen Antikörpers (Rituximab) verwendet werden kann und iv) dieser 90Nb-markierte mAb eine hohe in vitro Stabilität besitzt. Desweiteren wurde eine alternative und schnelle Abtrennungsmethode entwickelt, die es erlaubt 90Nb, mit einer geeigneten radiochemischen und radionuklidischen Reinheit für eine anschließende Markierung von Biomolekülen in einer Stunde zu aufzureinigen. Schließlich wurden erstmals 90Nb-markierte Biomolekülen in vivo untersucht. Desweiteren wurden auch Experimente durchgeführt, um den optimalen bifunktionellen Chelatbildner (BFC) für 90Niob zu finden. Mehrere BFC wurden hinsichtlich Komplexbildung mit NbV untersucht. Desferrioxamin (Df) erwies sich als geeignetster Chelator für 90Nb. Der monoklonale Antikörper Bevacizumab (Avastin®) wurde mit 90Nb markiert und eine Biodistributionsstudie und eine PET-Untersuchung durchgeführt. Alle diese Ergebnisse zeigten, dass 90Nb ein vielversprechendes Radionuklid für die Immuno-PET ist, welches sogar für weitere kommerzielle Anwendungen in der klinischen Routine geeignet zu sein scheint.rn

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The present study used positron emission tomography (PET) to examine the cerebral activity pattern associated with auditory imagery forfamiliar tunes. Subjects either imagined the continuation of nonverbaltunes cued by their first few notes, listened to a short sequence of notesas a control task, or listened and then reimagined that short sequence. Subtraction of the activation in the control task from that in the real-tune imagery task revealed primarily right-sided activation in frontal and superior temporal regions, plus supplementary motor area(SMA). Isolating retrieval of the real tunes by subtracting activation in the reimagine task from that in the real-tune imagery task revealedactivation primarily in right frontal areas and right superior temporal gyrus. Subtraction of activation in the control condition from that in the reimagine condition, intended to capture imagery of unfamiliarsequences, revealed activation in SMA, plus some left frontal regions. We conclude that areas of right auditory association cortex, together with right and left frontal cortices, are implicated in imagery for familiartunes, in accord with previous behavioral, lesion and PET data. Retrieval from musical semantic memory is mediated by structures in the right frontal lobe, in contrast to results from previous studies implicating left frontal areas for all semantic retrieval. The SMA seems to be involved specifically in image generation, implicating a motor code in this process.

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OBJECTIVE: To assess patterns of seroreactivity to Leptospira serovars in veterinary professional staff and dog owners exposed to dogs with acute leptospirosis and to contrast these patterns in people with those observed in dogs. DESIGN: Cross-sectional study. SAMPLE POPULATION: Human subjects consisted of 91 people (50 veterinarians, 19 technical staff, 9 administrative personnel, and 13 dog owners) exposed to dogs with leptospirosis. Canine subjects consisted of 52 dogs with naturally occurring leptospirosis admitted to the University of Bern Vetsuisse Faculty Small Animal Clinic in 2007 and 2008. PROCEDURES: People were tested for seroreactivity to regionally prevalent Leptospira serovars by use of a complement fixation test. A questionnaire designed to identify risk factors associated with seropositivity was used to collect demographic information from each study participant. Dogs were tested for seroreactivity to Leptospira serovars by use of a microscopic agglutination test. RESULTS: On the basis of microscopic agglutination test results, infected dogs were seropositive for antibodies against Leptospira serovars as follows (in descending order): Bratislava (43/52 [83%]), Australis (43/52 [83%]), Grippotyphosa (18/52 [35%]), Pomona (12/52 [23%]), Autumnalis (6/52 [12%]), Icterohemorrhagiae (4/52 [8%]), Tarassovi (2/52 [4%]), and Canicola (1/52 [2%]). All 91 people were seronegative for antibodies against Leptospira serovars. Therefore, statistical evaluation of risk factors and comparison of patterns of seroreactivity to Leptospira serovars between human and canine subjects were limited to theoretical risks. CONCLUSIONS AND CLINICAL RELEVANCE: Seroreactivity to Leptospira serovars among veterinary staff adhering to standard hygiene protocols and pet owners exposed to dogs with acute leptospirosis was uncommon.

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Gastrin-releasing peptide receptors (GRP-R) are upregulated in many cancers, including prostate, breast, and lung. We describe a new radiolabeled bombesin (BBN) analog for imaging and systemic radiotherapy that has improved pharmacokinetics (PK) and better retention of radioactivity in the tumor. METHODS: DO3A-CH2CO-G-4-aminobenzoyl-Q-W-A-V-G-H-L-M-NH2 (AMBA) was synthesized and radiolabeled. The human prostate cancer cell line PC-3 was used to determine the binding (Kd), retention, and efflux of 177Lu-AMBA. Receptor specificity was determined by in vitro autoradiography in human tissues. PK and radiotherapy studies were performed in PC-3 tumor-bearing male nude mice. RESULTS: 177Lu-AMBA has a high affinity for the GRP-R (Kd, 1.02 nmol/L), with a maximum binding capacity (Bmax) of 414 fmol/10(6) cells (2.5 x 10(5) GRP-R/cell). Internalization was similar for 177Lu-AMBA (76.8%), 177Lu-BBN8 (72.9%), and 125I-[Tyr4]-BBN (74.9%). Efflux was markedly lower for 177Lu-AMBA (2.9%) compared with 177Lu-BBN8 (15.9%) and 125I-[Tyr4]-BBN (46.1%). By receptor autoradiography, Lu-AMBA binds specifically to GRP-R (0.8 nmol/L) and to the neuromedin B receptor (NMB-R) (0.9 nmol/L), with no affinity for the bb3 receptor (>1,000 nmol/L). 177Lu-AMBA was renally excreted (55 %ID 1 h [percentage injected dose at 1 h]); tumor uptake at 1 and 24 h was 6.35 %ID/g and 3.39 %ID/g, respectively. One or 2 doses of 177Lu-AMBA (27.75 MBq/dose) significantly prolonged the life span of PC-3 tumor-bearing mice (P < 0.001 and P < 0.0001, respectively) and decreased PC-3 tumor growth rate over controls. When compared using World Health Organization criteria, mice receiving 2 doses versus 1 dose of 177Lu-AMBA demonstrated a shift away from stable/progressive disease toward complete/partial response; by RECIST (Response Evaluation Criteria in Solid Tumors), median survival increased by 36% and time to progression/progression-free survival increased by 65%. CONCLUSION: 177Lu-AMBA binds with nanomolar affinity to GRP-R and NMB-R, has low retention of radioactivity in kidney, demonstrates a very favorable risk-benefit profile, and is in phase I clinical trials.

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Somatostatin receptor PET tracers such as [68Ga-DOTA,1-Nal3]-octreotide (68Ga-DOTANOC) and [68Ga-DOTA,Tyr3]-octreotate (68Ga-DOTATATE) have shown promising results in patients with neuroendocrine tumors, with a higher lesion detection rate than is achieved with 18F-fluorodihydroxyphenyl-l-alanine PET, somatostatin receptor SPECT, CT, or MR imaging. 68Ga-DOTANOC has high affinity for somatostatin receptor subtypes 2, 3, and 5 (sst2,3,5). It has a wider receptor binding profile than 68Ga-DOTATATE, which is sst2-selective. The wider receptor binding profile might be advantageous for imaging because neuroendocrine tumors express different subtypes of somatostatin receptors. The goal of this study was to prospectively compare 68Ga-DOTANOC and 68Ga-DOTATATE PET/CT in the same patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and to evaluate the clinical impact of 68Ga-DOTANOC PET/CT. Methods: Eighteen patients with biopsy-proven GEP-NETs were evaluated with 68Ga-DOTANOC and 68Ga-DOTATATE using a randomized crossover design. Labeling of DOTANOC and DOTATATE with 68Ga was standardized using a fully automated synthesis device. PET/CT findings were compared with 3-phase CT scans and in some patients with MR imaging, 18F-FDG PET/CT, and histology. Uptake in organs and tumor lesions was quantified and compared by calculation of maximum standardized uptake values (SUVmax) using volume computer-assisted reading. Results: Histology revealed low-grade GEP-NETs (G1) in 4 patients, intermediate grade (G2) in 7, and high grade (G3) in 7. 68Ga-DOTANOC and 68Ga-DOTATATE were false-negative in only 1 of 18 patients. In total, 248 lesions were confirmed by cross-sectional and PET imaging. The lesion-based sensitivity of 68Ga-DOTANOC PET was 93.5%, compared with 85.5% for 68Ga-DOTATATE PET (P = 0.005). The better performance of 68Ga-DOTANOC PET is attributed mainly to the significantly higher detection rate of liver metastases rather than tumor differentiation grade. Multivariate analysis revealed significantly higher SUVmax in G1 tumors than in G3 tumors (P = 0.009). This finding was less pronounced with 68Ga-DOTANOC (P > 0.001). Altogether, 68Ga-DOTANOC changed treatment in 3 of 18 patients (17%). Conclusion: The sst2,3,5-specific radiotracer 68Ga-DOTANOC detected significantly more lesions than the sst2-specific radiotracer 68Ga-DOTATATE in our patients with GEP-NETs. The clinical relevance of this finding has to be proven in larger studies.

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Hemodialysis (HD) is a renal replacement therapy that can enable recovery of patients in acute kidney failure and prolong survival for patients with end-stage kidney failure. HD is also uniquely suited for management of refractory volume overload and removal of certain toxins from the bloodstream. Over the last decade, veterinary experience with HD has deepened and refined and its geographic availability has increased. As awareness of the usefulness and availability of dialytic therapy increases among veterinarians and pet owners and the number of veterinary dialysis facilities increases, dialytic management will become the standard of advanced care for animals with severe intractable uremia.

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The gastrin-releasing peptide receptor (GRPr) is an important molecular target for the visualization and therapy of tumors and can be targeted with radiolabeled bombesin derivatives. The present study aims to develop statine-based bombesin receptor antagonists suitable for labeling with 64Cu for imaging by positron emission tomography (PET). The potent GRPr antagonist D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 was conjugated to the sarcophagine (3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane=Sar) derivative 5-(8-methyl-3,6,10,13,16,19-hexaaza-bicyclo[6.6.6]icosan-1-ylamino)-5-oxopentanoic acid (MeCOSar) via PEG4 (LE1) and PEG2 (LE2) spacers and radiolabeled with 64Cu2+ with >95% yield and specific activities of about 100 MBq/nmol. Both Cu(II) conjugates have high affinity for GRPr (IC50: natCu-LE1, 1.4±0.1 nM; natCu-LE2, 3.8±0.6 nM). The antagonistic properties of both conjugates were confirmed by Ca2+-flux measurements. Biodistribution studies of Cu-64-LE1 exhibited specific targeting of the tumor (19.6±4.7% IA/g at 1 h p.i.) and GRPr-positive organs. Biodistribution and PET images at 4 and 24 h postinjection showed increasing tumor-to-background ratios with time. This was illustrated by the acquisition of PET images showing high tumor-to-normal tissue contrast. This study demonstrates the high affinity of the MeCOSar-PEGx-bombesin conjugates to GRPr. The stability of 64Cu complexes of MeCOSar, the long half-life of 64Cu, and the suitable biodistribution profile of the 64Cu-labeled peptides lead to PET images of high contrast suitable for potential translation into the clinic.

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PURPOSE Our main objective was to prospectively determine the prognostic value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) after two cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone given every 14 days (R-CHOP-14) under standardized treatment and PET evaluation criteria. PATIENTS AND METHODS Patients with any stage of diffuse large B-cell lymphoma were treated with six cycles of R-CHOP-14 followed by two cycles of rituximab. PET/CT examinations were performed at baseline, after two cycles (and after four cycles if the patient was PET-positive after two cycles), and at the end of treatment. PET/CT examinations were evaluated locally and by central review. The primary end point was event-free survival at 2 years (2-year EFS). RESULTS Median age of the 138 evaluable patients was 58.5 years with a WHO performance status of 0, 1, or 2 in 56%, 36%, or 8% of the patients, respectively. By local assessment, 83 PET/CT scans (60%) were reported as positive and 55 (40%) as negative after two cycles of R-CHOP-14. Two-year EFS was significantly shorter for PET-positive compared with PET-negative patients (48% v 74%; P = .004). Overall survival at 2 years was not significantly different, with 88% for PET-positive versus 91% for PET-negative patients (P = .46). By using central review and the Deauville criteria, 2-year EFS was 41% versus 76% (P < .001) for patients who had interim PET/CT scans after two cycles of R-CHOP-14 and 24% versus 72% (P < .001) for patients who had PET/CT scans at the end of treatment. CONCLUSION Our results confirmed that an interim PET/CT scan has limited prognostic value in patients with diffuse large B-cell lymphoma homogeneously treated with six cycles of R-CHOP-14 in a large prospective trial. At this point, interim PET/CT scanning is not ready for clinical use to guide treatment decisions in individual patients.

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Purpose: Traditional patient-specific IMRT QA measurements are labor intensive and consume machine time. Calculation-based IMRT QA methods typically are not comprehensive. We have developed a comprehensive calculation-based IMRT QA method to detect uncertainties introduced by the initial dose calculation, the data transfer through the Record-and-Verify (R&V) system, and various aspects of the physical delivery. Methods: We recomputed the treatment plans in the patient geometry for 48 cases using data from the R&V, and from the delivery unit to calculate the “as-transferred” and “as-delivered” doses respectively. These data were sent to the original TPS to verify transfer and delivery or to a second TPS to verify the original calculation. For each dataset we examined the dose computed from the R&V record (RV) and from the delivery records (Tx), and the dose computed with a second verification TPS (vTPS). Each verification dose was compared to the clinical dose distribution using 3D gamma analysis and by comparison of mean dose and ROI-specific dose levels to target volumes. Plans were also compared to IMRT QA absolute and relative dose measurements. Results: The average 3D gamma passing percentages using 3%-3mm, 2%-2mm, and 1%-1mm criteria for the RV plan were 100.0 (σ=0.0), 100.0 (σ=0.0), and 100.0 (σ=0.1); for the Tx plan they were 100.0 (σ=0.0), 100.0 (σ=0.0), and 99.0 (σ=1.4); and for the vTPS plan they were 99.3 (σ=0.6), 97.2 (σ=1.5), and 79.0 (σ=8.6). When comparing target volume doses in the RV, Tx, and vTPS plans to the clinical plans, the average ratios of ROI mean doses were 0.999 (σ=0.001), 1.001 (σ=0.002), and 0.990 (σ=0.009) and ROI-specific dose levels were 0.999 (σ=0.001), 1.001 (σ=0.002), and 0.980 (σ=0.043), respectively. Comparing the clinical, RV, TR, and vTPS calculated doses to the IMRT QA measurements for all 48 patients, the average ratios for absolute doses were 0.999 (σ=0.013), 0.998 (σ=0.013), 0.999 σ=0.015), and 0.990 (σ=0.012), respectively, and the average 2D gamma(5%-3mm) passing percentages for relative doses for 9 patients was were 99.36 (σ=0.68), 99.50 (σ=0.49), 99.13 (σ=0.84), and 98.76 (σ=1.66), respectively. Conclusions: Together with mechanical and dosimetric QA, our calculation-based IMRT QA method promises to minimize the need for patient-specific QA measurements by identifying outliers in need of further review.

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Cellular oncogenes and tumor suppressor genes regulate cellular adhesion and proliferation, two important events in malignant transformation. Even though receptor-like protein tyrosine phosphatases (R-PTPs) can influence these events, their role in malignant transformation has not been studied. The major goal of this study was to determine whether downregulation of R-PTP$\mu$ expression in lung epithelial cells is associated with or causal to neoplastic transformation. Examination of R-PTP$\mu$ expression in normal and carcinoma cells demonstrated that lung epithelial cells expressed R-PTP$\mu$ whereas lung carcinoma cells did not, and that incubation with TGF-$\alpha$ and HGF induced a two fold increase in R-PTP$\mu$ mRNA expression. To associate the expression of R-PTP$\mu$ with neoplastic transformation, we transfected lung epithelial cells with the H-ras oncogene. Transformation resulted in the activation of the MAPK signal transduction pathway, the hyperphosphorylation of c-met, and the production of HGF. Upon analysis of R-PTP$\mu$ expression, we observed a significant decrease in R-PTP$\mu$ mRNA and protein levels suggesting that transformation can directly or indirectly downregulate the expression of R-PTP$\mu.$ TGF-$\beta$ reversed the H-ras transformed phenotype, an event directly correlated with upregulation of R-PTP$\mu.$ To provide a casual relationship between R-PTP$\mu$ and cessation of tumor cell growth, we transfected carcinoma cells with the wild type R-PTP$\mu$ cDNA. Transiently expressing cells were selected by FACS using the mAb 3D7 and plated into individual wells. Carcinoma cells positive for R-PTP$\mu$ expression did not grow into colonies whereas non-R-PTP$\mu$ expressing carcinoma cells did, suggesting that expression of R-PTP$\mu$ arrested cell growth. To better understand the growth arrest induced by R-PTP$\mu$, we transfected the H-ras transformed lung epithelial cell line (MvLu-1-ras) with R-PTP$\mu$ (MvLu-1-ras/R-PTP$\mu$). Examination of growth factor receptor phosphorylation revealed significant inhibition of c-met and EGF-R. Furthermore, these cells underwent apoptosis in the absence of serum. Taken together the data demonstrate that the downregulation of R-PTP$\mu$ expression is an important step in neoplastic transformation of lung epithelial cells and that its presence can induce apoptosis and inhibit the signaling of c-met and EGF-R, two major growth factor receptors in lung carcinoma. In conclusion, the expression of R-PTP$\mu$ is inversely correlated with neoplastic transformation, growth and survival of tumor cells. ^

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Tit. en la etiqueta: "E. Pons / Valencia - España / sweet and juicy R.E. 8344 / Get-it"