Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
1.
Antibiotics (Basel) ; 13(9)2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39335030

RESUMO

OBJECTIVES: Ongoing research has begun to develop innovative approaches to deliver local antibiotics while minimizing systemic side effects, antimicrobial resistance, and limited tissue penetration. Autologous platelet concentrates (APCs) offer promise in delivering antibiotics directly to infection sites. Despite the interest, a comprehensive evaluation of their effectiveness is lacking. Therefore, this systematic scoping review aims to collect and appraise studies regarding the efficacy of APCs in delivering antibiotics. METHODS: A systematic electronic search of PubMed, Scopus, and Web of Science, using a combination of keywords, was conducted up to February 2024. Articles addressing the use of APCs as a local antibiotic delivery system were included. RESULTS: A total of 13 articles, including 10 in vitro studies, 1 in vitro and clinical study, 1 ex vivo study, and 1 clinical study, were selected. Antibiotic loading capacity and release was confirmed in all studies using doxycycline, gentamicin, linezolid, vancomycin, metronidazole, and penicillin. In addition, the antibacterial effect was obtained mainly against E. coli., P. aeruginosa, S. mitis, H. influenzae, S. pneumoniae, and S. aureus. CONCLUSIONS: The incorporation of antibiotics into APCs has been proven to facilitate the effective release of antimicrobial agents at optimal concentrations, potentially reducing the incidence of post-operative infections, substituting, or augmenting systemic antibiotic treatment while retaining APCs' inherent healing properties.

2.
J Clin Med ; 13(17)2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39274556

RESUMO

Ameloblastoma is a rare, benign, but locally aggressive odontogenic tumor that originates from the epithelial cells involved in tooth development. The surgical approach to treating an ameloblastoma depends on the type, size, location, and extent of the tumor, as well as the patient's age and overall health. This umbrella review's aim is to summarize the findings from systematic reviews (SRs) and meta-analyses on the effect of radical or conservative treatment of ameloblastoma on the recurrence rate and quality of life, to evaluate the methodological quality of the included SRs and discuss the clinical management. Three electronic databases (PubMed, Scopus, The Cochrane Library) were checked. The primary outcome was the recurrence rate after surgical treatment, while the secondary outcomes were the post-operative complications, quality of life, esthetic, and functional impairment. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Eighteen SRs were included. The quality of the included reviews ranged from critically low (three studies) to high (eight studies). Four studies were included in meta-analysis, and they revealed that the recurrence rate is about three-times more likely in the conservative treatment group compared to the radical treatment group, and this result is statistically significant. Despite the high recurrence rate, the latter was more appropriate in the case of smaller lesions and younger patients, due to better post-operative quality of life and reduced functional and esthetic impairments. Based on the results of this overview, conservative treatment may be recommended as the first-line approach for intraosseous ameloblastoma not involving soft tissue. However, given the expectation of a higher recurrence rate, it is advisable to reduce the interval between follow-up visits. However, further prospective studies are needed to establish the best treatment choice and follow-up period.

4.
Dent J (Basel) ; 12(4)2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38668013

RESUMO

Maxillary sinus augmentation is one of the most predictable procedures for the rehabilitation of the posterior maxilla. The current overview aimed to summarize the findings provided by systematic reviews (SRs) and meta-analyses on the effectiveness of autologous platelet concentrates (APCs) in sinus lift and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs and meta-analyses addressing the effectiveness of APCs in sinus lift technique were included. Clinical, radiographic and histomorphometric findings were considered for APCs as solely grafting materials and APCs in combination with biomaterials. Outcomes were implant survival rate (ISR), implant stability (IS), implant failure (IF), postoperative complications, histomorphometric findings, radiographic bone gain, bone volume and bone density. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Thirty SRs were included. The methodological quality of the included reviews ranged from critically low (3 studies) to high (9 studies). The included SRs showed favorable clinical outcomes, short-term new bone formation and no biological complications when APCs were used both as solely graft material or in combination with other biomaterials. However, no significant additional effects in the long-term period were observed. APCs did not add any further positive effects compared to the physiological healing derived by the natural blood clot. The current overview of SRs highlighted the need for high-quality SRs evaluating the role of APCs in sinus lift though network meta-analyses, in order to identify the most powerful material for sinus lift augmentation. The use of APCs improves the healing of soft tissues and the postoperative quality of life in the short-term period. Thus, its application can be recommended.

6.
J Clin Med ; 12(16)2023 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-37629387

RESUMO

One of the common challenges in oral surgery is dealing with patients who are taking oral anticoagulant/antiaggregant drugs. Several local hemostatic agents have been proposed as an alternative to conventional suturing. Among these, autologous platelet concentrates (APCs) have been widely used to decrease the risk of hemorrhage after dental extraction. Nevertheless, there is a lack of consensus regarding the superiority of any one specific hemostatic agent over the others. This systematic review is aimed at evaluating the effectiveness of APCs as hemostatic agents after tooth extraction in patients on anticoagulant therapy. A literature search was conducted of articles published before March 2023 on PubMed, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL). Studies on the use of APCs in patients undergoing dental extractions and being treated with anticoagulant drugs were included. Only randomized, controlled trials (RCTs) published up to March 2023 were included; the outcomes assessed were the time to hemostasis, the presence of post-operative bleeding and pain, and the effectiveness of wound healing. The risk of bias for each RCT was assessed by using the 'risk of bias' tool (RoB 1.0). The research revealed 6 RCTs. The findings indicated that patients on anticoagulant therapy who received APCs without discontinuing their medication experienced a decreased post-operative bleeding, a shorter hemostasis time, reduced pain, and accelerated wound healing. However, due to the high/unclear risk of bias of the studies included, no definitive conclusions can be drawn on the superiority of APCs as hemostatic agents over other similar products. Additional studies are required to validate these findings.

7.
ACS Chem Biol ; 18(8): 1880-1890, 2023 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-37494676

RESUMO

Ghrelin O-acyltransferase (GOAT) plays a central role in the maturation and activation of the peptide hormone ghrelin, which performs a wide range of endocrinological signaling roles. Using a tight-binding fluorescent ghrelin-derived peptide designed for high selectivity for GOAT over the ghrelin receptor GHSR, we demonstrate that GOAT interacts with extracellular ghrelin and facilitates ligand cell internalization in both transfected cells and prostate cancer cells endogenously expressing GOAT. Coupled with enzyme mutagenesis, ligand uptake studies support the interaction of the putative histidine general base within GOAT with the ghrelin peptide acylation site. Our work provides a new understanding of GOAT's catalytic mechanism, establishes that GOAT can interact with ghrelin and other peptides located outside the cell, and raises the possibility that other peptide hormones may exhibit similar complexity in their intercellular and organismal-level signaling pathways.


Assuntos
Grelina , Via Secretória , Animais , Masculino , Aciltransferases/metabolismo , Corantes , Grelina/metabolismo , Ligantes
8.
Int J Hyg Environ Health ; 248: 114117, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36708652

RESUMO

BACKGROUND: Inhalation of Legionella-containing aerosols generated by cooling towers (CT) and evaporative condensers (EC) where water risk management is not performed correctly has been linked to a high percentage of community outbreaks of Legionnaires' disease (LD). Likewise, microbiological and physicochemical characteristics of the water in these facilities have been associated with this bacterium. The main aim of this study was to assess the risk of Legionella colonization in CT and EC based on the data for microbiological and physicochemical water quality provided by the Environmental Health Department and Laboratory of the City Council of L'Hospitalet de Llobregat (Barcelona, Spain). METHODS: Legionella was analysed in 789 samples collected from 127 CT and EC in 46 companies in Catalonia from 2002 to 2019. A two-step logistic regression analysis was carried out to assess the risk of colonization by Legionella in the studied facilities according to the microbiological (aerobic heterotrophic bacteria) and physicochemical (pH, alkalinity, hardness, turbidity, conductivity, total iron and Langelier Index) water parameters. The optimal cut-off points for the water parameters predictive of Legionella contamination were defined as the values on the receiver operating characteristic (ROC) curve where sensitivity and specificity were jointly maximized. RESULTS: Legionella was isolated in 8.49% of the 789 analysed samples, 22.39% of which were heavily contaminated (with counts higher than 1.0 × 104 CFU/l). L. pneumophila was isolated in 82.09% of the samples, with 41.82% belonging to serogroup 1. Logistic regression analysis revealed that aerobic heterotrophic bacteria concentrations ≥6.90 × 102 CFU/ml [Odds ratios (OR) (95% CI) = 3.56 (1.39-9.43), p = 0.01], a pH ≥ 8.70 [OR (95% CI) = 3.60 (1.34-10.09), p = 0.01], and water hardness ≥5.72 × 102 mg/l [OR (95% CI) = 6.30 (2.34-18.56), p < 0.001] were each independently associated with a higher risk of CT and EC colonization by Legionella. CONCLUSIONS: The present study shows the importance of risk assessment for improving the control measures aimed at preventing or reducing Legionella populations in CT and EC, thus minimizing potential dangers for public health.


Assuntos
Legionella pneumophila , Legionella , Doença dos Legionários , Humanos , Microbiologia da Água , Aerossóis e Gotículas Respiratórios , Doença dos Legionários/epidemiologia , Doença dos Legionários/microbiologia
9.
bioRxiv ; 2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38234806

RESUMO

The platelet-derived growth factor receptor (PDGFR) family of receptor tyrosine kinases allows cells to communicate with one another by binding to growth factors at the plasma membrane and activating intracellular signaling pathways to elicit responses such as migration, proliferation, survival and differentiation. The PDGFR family consists of two receptors, PDGFRα and PDGFRß, that dimerize to form PDGFRα homodimers, PDGFRα/ß heterodimers and PDGFRß homodimers. Here, we overcame prior technical limitations in visualizing and purifying PDGFRα/ß heterodimers by generating a cell line stably expressing C-terminal fusions of PDGFRα and PDGFRß with bimolecular fluorescence complementation fragments corresponding to the N-terminal and C-terminal regions of the Venus fluorescent protein, respectively. We found that these receptors heterodimerize relatively quickly in response to PDGF-BB ligand treatment, with a peak of receptor autophosphorylation following 5 minutes of ligand stimulation. Moreover, we demonstrated that PDGFRα/ß heterodimers are rapidly internalized into early endosomes, particularly signaling endosomes, where they dwell for extended lengths of time. We showed that PDGFRα/ß heterodimer activation does not induce downstream phosphorylation of ERK1/2 and significantly inhibits cell proliferation. Further, we characterized the PDGFR dimer-specific interactome and identified MYO1D as a novel protein that preferentially binds PDGFRα/ß heterodimers. We demonstrated that knockdown of MYO1D leads to retention of PDGFRα/ß heterodimers at the plasma membrane, resulting in increased phosphorylation of ERK1/2 and increased cell proliferation. Collectively, our findings impart valuable insight into the molecular mechanisms by which specificity is introduced downstream of PDGFR activation to differentially propagate signaling and generate distinct cellular responses.

10.
J Cell Sci ; 135(17)2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35946433

RESUMO

Signaling through the platelet-derived growth factor receptors (PDGFRs) plays a critical role in multiple cellular processes during development. The two PDGFRs, PDGFRα and PDGFRß, dimerize to form homodimers and/or heterodimers. Here, we overcome previous limitations in studying PDGFR dimer-specific dynamics by generating cell lines stably expressing C-terminal fusions of each PDGFR with bimolecular fluorescence complementation (BiFC) fragments corresponding to the N-terminal or C-terminal regions of the Venus fluorescent protein. We find that PDGFRß receptors homodimerize more quickly than PDGFRα receptors in response to PDGF ligand, with increased levels of autophosphorylation. Furthermore, we demonstrate that PDGFRα homodimers are trafficked and degraded more quickly, whereas PDGFRß homodimers are more likely to be recycled back to the cell membrane. We show that PDGFRß homodimer activation results in a greater amplitude of phospho-ERK1/2 and phospho-AKT signaling, as well as increased proliferation and migration. Finally, we demonstrate that inhibition of clathrin-mediated endocytosis leads to changes in cellular trafficking and downstream signaling, particularly for PDGFRα homodimers. Collectively, our findings provide significant insight into how biological specificity is introduced to generate unique responses downstream of PDGFR engagement. This article has an associated First Person interview with the first author of the paper.


Assuntos
Receptor alfa de Fator de Crescimento Derivado de Plaquetas , Transdução de Sinais , Humanos , Fosforilação , Multimerização Proteica , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/genética , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo
11.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1392453

RESUMO

Objetivo: Analizar los aceites esenciales como tratamiento para el estrés. Método: Revisión sistemática de articulos referentes al tema de investigación, en plataformas como: PubMed, Scielo, Scopus, donde se seleccionaron 15 artículos de referencia directa al tema investigado. Conclusión: La evidencia escrutada ha demostrado la eficacia del uso de aceites esenciales ya que, además de ser percibido como un aroma agradable, también influyó al reducir los niveles de estrés, ansiedad, depresión; al provocar un estado de sedación relajante y descanso mental, lo que constituye en un bienestar psicológico para que el individuo pueda desarrollarse mejor en su entorno y labores cotidianas.


Objective: To analyze essential oils as a treatment for stress. Method: Systematic review of articles referring to the research topic, in platforms such as: PubMed, Scielo, Scopus, where 15 articles of direct reference to the researched topic were selected. Conclusion: The evidence scrutinized has demonstrated the efficacy of the use of essential oils since, in addition to being perceived as a pleasant aroma, it also influenced by reducing the levels of stress, anxiety, depression; by causing a state of relaxing sedation and mental rest, which constitutes a psychological well-being so that the individual can develop better in their environment and daily work.

12.
PLoS Negl Trop Dis ; 15(7): e0009605, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34324509

RESUMO

BACKGROUND: Regulatory T cells (Tregs) play a critical role during Mycobacterium tuberculosis (Mtb) infection, modulating host responses while neutralizing excessive inflammation. However, their impact on regulating host protective immunity is not completely understood. Here, we demonstrate that Treg cells abrogate the in vitro microbicidal activity against Mtb. METHODS: We evaluated the in vitro microbicidal activity of peripheral blood mononuclear cells (PBMCs) from patients with active tuberculosis (TB), individuals with latent tuberculosis infection (LTBI, TST+/IGRA+) and healthy control (HC, TST-/IGRA-) volunteers. PBMCs, depleted or not of CD4+CD25+ T-cells, were analyzed to determine frequency and influence on microbicidal activity during in vitro Mtb infection with four clinical isolates (S1, S5, R3, and R6) and one reference strain (H37Rv). RESULTS: The frequency of CD4+CD25highFoxP3+ cells were significantly higher in Mtb infected whole blood cultures from both TB patients and LTBI individuals when compared to HC. Data from CD4+CD25+ T-cells depletion demonstrate that increase of CD4+CD25highFoxP3+ is associated with an impairment of Th-1 responses and a diminished in vitro microbicidal activity of LTBI and TB groups. CONCLUSIONS: Tregs restrict host anti-mycobacterial immunity during active disease and latent infection and thereby may contribute to both disease progression and pathogen persistence.


Assuntos
Atividade Bactericida do Sangue , Antígenos CD4/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Tuberculose Latente/imunologia , Mycobacterium tuberculosis/imunologia , Tuberculose Pulmonar/imunologia , Antígenos CD4/genética , Estudos de Casos e Controles , Fatores de Transcrição Forkhead/genética , Humanos , Subunidade alfa de Receptor de Interleucina-2/genética , Linfócitos T Reguladores
13.
Oncogene ; 39(19): 3952-3964, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32203168

RESUMO

The elimination of DNA polymerase eta (pol η) causes discontinuous DNA elongation and fork stalling in UV-irradiated cells. Such alterations in DNA replication are followed by S-phase arrest, DNA double-strand break (DSB) accumulation, and cell death. However, their molecular triggers and the relative timing of these events have not been fully elucidated. Here, we report that DSBs accumulate relatively early after UV irradiation in pol η-depleted cells. Despite the availability of repair pathways, DSBs persist and chromosome instability (CIN) is not detectable. Later on cells with pan-nuclear γH2AX and massive exposure of template single-stranded DNA (ssDNA), which indicate severe replication stress, accumulate and such events are followed by cell death. Reinforcing the causal link between the accumulation of pan-nuclear ssDNA/γH2AX signals and cell death, downregulation of RPA increased both replication stress and the cell death of pol η-deficient cells. Remarkably, DSBs, pan-nuclear ssDNA/γH2AX, S-phase arrest, and cell death are all attenuated by MRE11 nuclease knockdown. Such results suggest that unscheduled MRE11-dependent activities at replicating DNA selectively trigger cell death, but not CIN. Together these results show that pol η-depletion promotes a type of cell death that may be attractive as a therapeutic tool because of the lack of CIN.


Assuntos
Quebras de DNA de Cadeia Dupla/efeitos da radiação , DNA Polimerase Dirigida por DNA/genética , Histonas/genética , Proteína Homóloga a MRE11/genética , Pontos de Checagem do Ciclo Celular/efeitos da radiação , Morte Celular/genética , Instabilidade Cromossômica/efeitos da radiação , Dano ao DNA/efeitos da radiação , Reparo do DNA/efeitos da radiação , Replicação do DNA/efeitos da radiação , DNA de Cadeia Simples/efeitos da radiação , Humanos , Fase S/efeitos da radiação , Raios Ultravioleta/efeitos adversos
14.
J Biol Chem ; 294(39): 14166-14174, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31413115

RESUMO

Integral membrane proteins represent a large and diverse portion of the proteome and are often recalcitrant to purification, impeding studies essential for understanding protein structure and function. By combining co-evolutionary constraints and computational modeling with biochemical validation through site-directed mutagenesis and enzyme activity assays, we demonstrate here a synergistic approach to structurally model purification-resistant topologically complex integral membrane proteins. We report the first structural model of a eukaryotic membrane-bound O-acyltransferase (MBOAT), ghrelin O-acyltransferase (GOAT), which modifies the metabolism-regulating hormone ghrelin. Our structure, generated in the absence of any experimental structural data, revealed an unanticipated strategy for transmembrane protein acylation with catalysis occurring in an internal channel connecting the endoplasmic reticulum lumen and cytoplasm. This finding validated the power of our approach to generate predictive structural models for other experimentally challenging integral membrane proteins. Our results illuminate novel aspects of membrane protein function and represent key steps for advancing structure-guided inhibitor design to target therapeutically important but experimentally intractable membrane proteins.


Assuntos
Aciltransferases/química , Domínio Catalítico , Acetilação , Aciltransferases/metabolismo , Animais , Grelina/química , Grelina/metabolismo , Humanos , Células Sf9 , Spodoptera
16.
Sci Rep ; 6: 19140, 2016 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-26751616

RESUMO

Using a strain-rosette, we demonstrate the existence of transverse strain using time-resolved x-ray diffraction from multiple Bragg reflections in laser-excited bulk gallium arsenide. We find that anisotropic strain is responsible for a considerable fraction of the total lattice motion at early times before thermal equilibrium is achieved. Our measurements are described by a new model where the Poisson ratio drives transverse motion, resulting in the creation of shear waves without the need for an indirect process such as mode conversion at an interface. Using the same excitation geometry with the narrow-gap semiconductor indium antimonide, we detected coherent transverse acoustic oscillations at frequencies of several GHz.

17.
Med Phys ; 42(9): 5055-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26328956

RESUMO

PURPOSE: Dual-energy (DE) imaging is a method that suppresses bony anatomy on planar kV images while enhancing soft tissue contrast. This technique has been used specifically in the chest to improve the visualization of small lung tumors. However, DE imaging may also provide quantitative information that has not been previously investigated. In this study, the aim was to establish a theoretical relationship between DE image contrast and tumor thickness and to observe this trend in phantom experiments. METHODS: A phantom consisting cork (used to simulate lung), tissue-equivalent material, and pork ribs was constructed to test for a relationship between DE image contrast and simulated tumor thickness. Fifteen phantom setups were used with various thicknesses of cork and tissue-equivalent material. For each setup, high (120 kVp) and low (60 kVp) energy planar images were acquired and DE images were produced. The image contrast between the simulated tumor and surrounding tissue was then plotted against the known thicknesses and a linear regression was performed. RESULTS: A linear regression of the contrast data vs simulated tumor thickness resulted in a slope of -0.0454 with an R(2) = 0.9904. The expected uncertainty in the thickness measurements using the regression parameters and DE contrast standard deviation was 0.13 cm. CONCLUSIONS: Phantom data exhibited a linear relationship between DE image contrast and simulated tumor thickness. Future studies will investigate patient-specific parameters so that this method can be used clinically to evaluate tumor thickness from planar kV images. Such an approach may have benefits for both adaptive and heavy ion therapies.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Tomografia Computadorizada por Raios X , Carga Tumoral , Humanos , Imagens de Fantasmas
18.
Med Phys ; 42(8): 4629-35, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26233190

RESUMO

PURPOSE: A multi-institutional planning study was performed to evaluate the frequency that current guidelines established by Radiation Therapy Oncology Group (RTOG) protocols and other literature for lung stereotactic body radiotherapy (SBRT) treatments are followed. METHODS: A total of 300 patients receiving lung SBRT treatments in four different institutions were retrospectively reviewed. The treatments were delivered using Linac based SBRT (160 patients) or image guided robotic radiosurgery (140). Most tumors were located peripherally (250/300). Median fractional doses and ranges were 18 Gy (8-20 Gy), 12 Gy (6-15 Gy), and 10 Gy (5-12 Gy) for three, four, and five fraction treatments, respectively. The following planning criteria derived from RTOG trials and the literature were used to evaluate the treatment plans: planning target volumes, PTVV 100 ≥ 95% and PTVV 95 ≥ 99%; conformality indices, CI100% < 1.2 and CI50% range of 2.9-5.9 dependent on PTV; total lung-ITV: V20Gy < 10%, V12.5Gy < 15%, and V5Gy < 37%; contralateral lung V5Gy < 26%; and maximum doses for spinal cord, esophagus, trachea/bronchus, and heart and great vessels. Populations were grouped by number of fractions, and dosimetric criteria satisfaction rates (CSRs) were reported. RESULTS: Five fraction regimens were the most common lung SBRT fractionation (46%). The median PTV was 27.2 cm(3) (range: 3.8-419.5 cm(3)). For all plans: mean PTVV 100 was 94.5% (±5.6%, planning CSR: 69.8%), mean PTVV 95 was 98.1% (±4.1%, CSR: 69.5%), mean CI100% was 1.14 (±0.21, CSR: 79.1%, and 16.5% within minor deviation), and mean CI50% was 5.63 (±2.8, CSR: 33.0%, and 28.0% within minor deviation). When comparing plans based on location, peripherally located tumors displayed higher PTVV 100 and PTVV 95 CSR (71.5% and 71.9%, respectively) than centrally located tumors (61.2% and 57.1%, respectively). Overall, the planning criteria were met for all the critical structure such as lung, heart, spinal cord, esophagus, and trachea/bronchus for at least 85% of the patients. CONCLUSIONS: Among the various parameters that were used to evaluate the SBRT plans, the CI100% and CI50% were the most challenging criteria to meet. Although the CSRs of organs at risk were higher among all cases, their proximity to the PTV was a significant factor.


Assuntos
Fidelidade a Diretrizes/estatística & dados numéricos , Radiocirurgia/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Humanos , Pulmão/efeitos da radiação , Neoplasias Pulmonares/cirurgia , Órgãos em Risco , Guias de Prática Clínica como Assunto , Radiocirurgia/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/métodos
19.
Med Phys ; 42(1): 254-62, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25563265

RESUMO

PURPOSE: To evaluate the efficacy of dual-energy (DE) vs single-energy (SE) fluoroscopic imaging of lung tumors using a markerless template-based tracking algorithm. METHODS: Ten representative patient breathing patterns were programmed into a Quasar™ motion phantom. The phantom was modified by affixing pork ribs to the surface, and a cedar insert with a small spherical volume was used to simulate lung and tumor, respectively. Sequential 60 kVp (6 mA) and 120 kVp (1.5 mA) fluoroscopic sequences were acquired. Frame-by-frame weighted logarithmic subtraction was performed resulting in a DE fluoroscopic sequence. A template-based algorithm was then used to track tumor motion throughout the DE and SE fluoroscopy sequences. Tracking coordinates were evaluated against ground-truth tumor locations. Fluoroscopic images were also acquired for two lung cancer patients, neither of which had implanted fiducials. RESULTS: For phantom imaging, a total of 1925 frames were analyzed. The algorithm successfully tracked the target on 99.9% (1923/1925) of DE frames vs 90.7% (1745/1925) SE images (p < 0.01). The displacement between tracking coordinates and ground truth for the phantom was 1.4 mm ± 1.1 mm for DE vs 2.0 mm ± 1.3 mm for SE (p < 0.01). Images from two patients, one with a larger tumor and one with a smaller tumor, were also analyzed. For the patient with the larger tumor, the average displacement from physician defined ground truth was 1.2 mm ± 0.6 mm for DE vs 1.4 mm ± 0.7 mm for SE (p = 0.016). For the patient that presented with a smaller tumor, the average displacement from physician defined ground truth was 2.2 mm ± 1.0 mm for DE vs 3.2 mm ± 1.4 mm for SE (p < 0.01). Importantly, for this single patient with the smaller tumor, 15.6% of the SE frames had >5 mm displacements from the ground truth vs 0% for DE fluoroscopy. CONCLUSIONS: This work indicates the potential for markerless tumor tracking utilizing DE fluoroscopy. With DE imaging, the algorithm showed improved detectability vs SE fluoroscopy and was able to accurately track the tumor in nearly all cases.


Assuntos
Algoritmos , Fluoroscopia/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Movimento (Física) , Idoso , Idoso de 80 Anos ou mais , Animais , Estudos de Viabilidade , Feminino , Fluoroscopia/instrumentação , Humanos , Masculino , Imagens de Fantasmas , Costelas , Suínos
20.
Anal Chim Acta ; 804: 221-7, 2013 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-24267085

RESUMO

Heparin, dextran sulfate (DS), chondroitin sulfate (CS), and carrageenan are found to enhance the luminescence intensity of an osmium(II) carbonyl complex with phenanthroline (phen) and 4-phenylpyridine (4-phpy) ligands in aqueous and ethanol solutions. The enhancing effect of the polyanions on the luminescence of the complex is heavily dependent on the sulfate content and other factors such as structure, solubility, and counter ions of the polyanion. The highly sulfated dextran and ι-carrageenan have the most profound effect, while the low charged κ-carrageenan and CS have the least response in aqueous solution. All polyanions exhibited enhanced luminescence intensity of the complex in ethanol solutions, and even the low charged CS and κ-carrageenan enhanced the luminescence more than 4 times. DS contamination of the sodium heparin at 5% can show a significant increase in luminescence response. The osmium complex is found to be highly successful in the fast and sensitive detection of heparin in commercial injectable samples with various backgrounds as well as the detection of CS in over the counter food supplement tablets.


Assuntos
Sulfatos de Condroitina/análise , Heparina/análise , Osmio/química , Polímeros/química , Luminescência , Polieletrólitos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA