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1.
Sci Rep ; 13(1): 17707, 2023 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-37853206

RESUMO

The blood-brain barrier (BBB) presents a significant challenge for targeted drug delivery. A proposed method to improve drug delivery across the BBB is focused ultrasound (fUS), which delivers ultrasound waves to a targeted location in the brain and is hypothesized to open the BBB. Furthermore, stem cell-derived exosomes have been suggested as a possible anti-inflammatory molecule that may have neural benefits, if able to pass the BBB. In the present study, transcranial low-intensity focused ultrasound (LIFU), without the use of intravenous microbubbles, was assessed for both (1) its ability to influence the BBB, as well as (2) its ability to increase the localization of intravenously administered small molecules to a specific region in the brain. In vivo rat studies were conducted with a rodent-customized 2 MHz LIFU probe (peak pressure = 1.5 MPa), and injection of labeled stem cell-derived exosomes. The results suggested that LIFU (without microbubbles) did not appear to open the BBB after exposure times of 20, 40, or 60 min; instead, there appeared to be an increase in transcytosis of the dextran tracer. Furthermore, the imaging results of the exosome study showed an increase in exosome localization in the right hippocampus following 60 min of targeted LIFU.


Assuntos
Exossomos , Ratos , Animais , Encéfalo/diagnóstico por imagem , Barreira Hematoencefálica/diagnóstico por imagem , Ultrassonografia , Sistemas de Liberação de Medicamentos/métodos , Microbolhas , Imageamento por Ressonância Magnética
2.
Respir Physiol Neurobiol ; 315: 104109, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37393966

RESUMO

Interstitial lung diseases (ILD) are a heterogenic group of respiratory diseases with complex pathogenesis. A growing number of evidence suggests role of adipose tissue and it's hormones (adipokines) in pathogenesis of various disorders, including lung tissue diseases. The aim of this study was to assess the concentrations of selected adipokines and their receptors (apelin, adiponectin, chemerin, chemerin receptor - CMKLR1) in patients with IPF (idiopathic pulmonary fibrosis) and sarcoidosis in comparison to healthy controls. We found changes in adipokines concentrations in ILD. Adiponectin concentrations were higher in all respiratory diseases patients in comparison to healthy controls. Apelin concentration in ILD patients was higher then those in healthy subjects. The trend of chemerin and CMKLR1 concentrations were similar, with highest concentrations seen in sarcoidosis. The study shows a difference of adipokines concentrations between patients with ILD and healthy controls. Adipokines are a potential marker and therapeutic target in patients with IPF and sarcoidosis.


Assuntos
Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Doenças Respiratórias , Sarcoidose , Humanos , Adipocinas , Apelina , Adiponectina , Sarcoidose/complicações
3.
J Plast Reconstr Aesthet Surg ; 73(12): 2210-2216, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32536461

RESUMO

Botulinum toxin is a treatment whose effectiveness has been widely demonstrated in the treatment of facial wrinkles. Its use in alopecia has been much less studied in the literature. Therefore, we carried out a systematic review of the literature in December 2019 in order to index published cases of alopecia patients treated with botulinum toxin. Pub Med, Embase, and Cochrane Library databases were explored. Six studies that included 94 patients were selected. Only one study was prospectively controlled against placebo. Of the 94 patients, 85 were affected by androgenetic alopecia, 8 by alopecia areata, and 1 by radiation-induced alopecia. The doses injected per session varied between 30 and 150 units and the number of sessions between 1 and 12. In the majority of the studies, the injections were carried out in all the muscles of the scalp (frontal, temporal, peri-auricular, occipital). Four studies showed a frank improvement in hair growth. Two of them showed improvement in hair density using an objective endpoint (hair count). The remaining reported studies showed inconclusive results. Patient satisfaction was high across all studies, but this systematic review did not clearly demonstrate the value of using the botulinum toxin in the treatment of alopecia. Subsequent prospective randomized controlled studies are required.


Assuntos
Alopecia/tratamento farmacológico , Toxinas Botulínicas Tipo A/uso terapêutico , Técnicas Cosméticas , Humanos , Couro Cabeludo/efeitos dos fármacos
4.
Sci Rep ; 9(1): 19310, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31848431

RESUMO

The levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the Pilica River and Sulejów Reservoir were found to be 46% higher during the flood season than during stable flow periods. In addition, PCDD/PCDF and dl-PCB mass loads increased by 5- to 12-fold and by 23- to 60-fold for toxic equivalency (TEQ) during flooding. The Sulejów Reservoir was found to play a positive role in reducing PCDD, PCDF and dl-PCB transport within the study period, with reductions ranging from 17 to 83% for total concentrations, and 33 to 79% for TEQ. Wastewater Treatment Plants (WTPs) were not efficient at mass concentration removal, with small displaying the least efficiency. WTPs discharge pollutants into the aquatic environment, they also produce sludge that requires disposal, similar to reservoir sediments. Sludge- or sediment-born PCDDs, PCDFs and dl-PCBs may be removed using phytoremediation. The cultivation of cucumber and zucchini, two efficient phytoremediators of organic pollutants, on polluted substrate resulted in a mean decrease in PCDD + PCDF + dl-PCB TEQ concentrations: 64% for cucumber and 69% for zucchini in sludge-amended soil, and by 52% for cucumber and 51% for zucchini in sediment-amended soil.

5.
J Eur Acad Dermatol Venereol ; 33(9): 1742-1746, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31132182

RESUMO

BACKGROUND: Pruritus is a leading cause of reduced health-related quality of life (QoL) in atopic dermatitis (AD). Crisaborole ointment is a non-steroidal phosphodiesterase 4 inhibitor for the treatment of mild-to-moderate AD. In identical Phase 3 studies (NCT02118766, NCT02118792), crisaborole reduced disease and pruritus severity versus vehicle. OBJECTIVE: Quantify the relationship between pruritus and QoL using data from these studies. METHODS: Patients aged ≥2 years were randomly assigned 2 : 1 to receive crisaborole:vehicle twice daily for 28 days. QoL was measured at baseline and day 29 using the Dermatology Life Quality Index (DLQI; patients aged ≥16 years), the Children's Dermatology Life Quality Index (CDLQI; patients aged 2-15 years) and the Dermatitis Family Impact (DFI; caregivers of patients aged 2-17 years). Pruritus was measured using the Severity of Pruritus Scale (SPS), a 4-point scale from 0 ('no itching') to 3 ('bothersome itching/scratching that disturbs sleep'), and captured morning and evening via electronic diary. Data from crisaborole and vehicle arms were pooled for this analysis. A repeated-measures longitudinal model was used to estimate relationships between pruritus (SPS) and QoL (DLQI, CDLQI and DFI in separate analyses). RESULTS: One thousand five hundred and twenty two patients received crisaborole or vehicle. A linearity assumption for the relationship between SPS and DLQI (n = 294), CDLQI (n = 1200), and DFI (n = 1293) was appropriate. For DLQI, SPS score of 0 was associated with 'no negative effect on patient QoL'; SPS score of 1 was associated with 'small effect on patient QoL'; SPS score of 2 was associated with 'moderate effect on patient QoL'; and SPS score of 3 was associated with 'very large effect on patient QoL'. The pattern of relationships between SPS and CDLQI and DFI was similar. CONCLUSIONS: The relationships between SPS and DLQI, CDLQI and DFI substantiate the significant link between pruritus and patient/caregiver QoL in AD.


Assuntos
Compostos de Boro/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Dermatite Atópica/tratamento farmacológico , Prurido/tratamento farmacológico , Qualidade de Vida , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Método Duplo-Cego , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Pomadas , Índice de Gravidade de Doença
6.
J Immunol Res ; 2019: 2816498, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30944830

RESUMO

Regulatory T-cells (Tregs) are a very important subtype of lymphocytes when it comes to self-control in the human immunological system. Tregs are decisive not only in the protection against destruction of own tissues by autoimmune immunocompetent cells but also in the immunological answer to developing cancers. On the other hand, Tregs could be responsible for the progression of acute and chronic leukemias. In our study, we review publications available in the PUMED database concerning acute leukemia, with a particular emphasis on child's leukemias. The percentage of regulatory T-lymphocytes in peripheral blood and bone marrow was elevated compared to those in healthy individuals and correlated with progressive disease. Regulatory T-cells taken from children diagnosed with leukemia showed a higher suppressive capability, which was confirmed by detecting elevated levels of secreted IL-10 and TGF-beta. The possibility of pharmacological intervention in the self-control of the immunological system is now under extensive investigation in many human cancers. Presumably, Treg cells could be a vital part of targeted therapies. Routine Treg determination could be used to assess the severity of disease and prognosis in children with acute lymphoblastic leukemia. This proposition results from the fact that in some studies, higher percentage of Treg cells in peripheral blood was demonstrated. However, observations confirming these facts are scarce; thus, extrapolating them to the population of children with hematological malignancies needs to be verified in additional studies.


Assuntos
Leucemia Mieloide Aguda/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Linfócitos T Reguladores/imunologia , Progressão da Doença , Citometria de Fluxo , Fatores de Transcrição Forkhead/imunologia , Humanos , Imunofenotipagem , Interleucina-10/imunologia , Linfócitos T Reguladores/classificação , Fator de Crescimento Transformador beta/imunologia
7.
Transplant Proc ; 50(7): 1957-1961, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30177087

RESUMO

The "ECMO for Greater Poland" program takes full advantage of the extracorporeal membrane oxygenation (ECMO) perfusion therapy opportunities to promote the health of the 3.5 million inhabitants in the region. The main implementation areas are treatment of patients with hypothermia; severe reversible respiratory failure (RRF); critical states resulting in heart failure, that is, cardiac arrest, cardiogenic shock, or acute intoxication; and promotion of the donor after circulatory death (DCD) strategy in selected organ donor cases, after unsuccessful life-saving treatment, to achieve organ recovery. This organizational model is complex and expensive, so we used advanced high-fidelity medical simulation tests to prepare for real-life experience. Over the course of 4 months we performed scenarios including "ECMO for DCD," "ECMO for extended cardiopulmonary resuscitation," "ECMO for RRF," and "ECMO in hypothermia." Soon after these simulations, Maastricht category II DCD procedures were performed involving real patients and resulting in 2 successful double kidney transplantations for the first time in Poland. One month later we treated 2 hypothermia patients (7 adult patients with heart failure and 5 patients with reversible respiratory failure) with ECMO for the first time in the region. Fortunately, we have discovered an important new role of medical simulation. It can be used not only for skills testing but also as a tool to create non-existing procedures and unavailable algorithms. The result of these program activities will promote the care and treatment of patients in critical condition with ECMO therapy as well as increase the potential organ pool from DCDs in the Greater Poland region of Poland.


Assuntos
Oxigenação por Membrana Extracorpórea/educação , Oxigenação por Membrana Extracorpórea/métodos , Treinamento por Simulação/métodos , Obtenção de Tecidos e Órgãos/métodos , Adulto , Idoso , Algoritmos , Morte , Educação Médica , Feminino , Humanos , Hipotermia/terapia , Transplante de Rim , Masculino , Pessoa de Meia-Idade , Polônia , Doadores de Tecidos , Adulto Jovem
8.
Phys Med Biol ; 63(16): 165008, 2018 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-29992906

RESUMO

A novel whole-body positron emission tomography (PET) system based on plastic scintillators is developed by the J-PET Collaboration. It consists of plastic scintillator strips arranged axially in the form of a cylinder, allowing the cost-effective construction of the total-body PET system. In order to determine the properties of the scanner prototype and optimize its geometry, advanced computer simulations were performed using the GATE (Geant4 application for tomographic emission) software. The spatial resolution, sensitivity, scatter fraction and noise equivalent count rate were estimated according to the National Electrical Manufacturers Association norm, as a function of the length of the tomograph, the number of detection layers, the diameter of the tomographic chamber and for various types of applied readout. For the single-layer geometry with a diameter of 85 cm, a strip length of 100 cm, a cross-section of 4 mm × 20 mm and silicon photomultipliers with an additional layer of wavelength shifter as the readout, the spatial resolution (full width at half maximum) in the centre of the scanner is equal to 3 mm (radial, tangential) and 6 mm (axial). For the analogous double-layer geometry with the same readout, diameter and scintillator length, with a strip cross-section of 7 mm × 20 mm, a noise equivalent count rate peak of 300 kcps was reached at 40 kBq cc-1 activity concentration, the scatter fraction is estimated to be about 35% and the sensitivity at the centre amounts to 14.9 cps kBq-1. Sensitivity profiles were also determined.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Imagens de Fantasmas , Tomografia por Emissão de Pósitrons/instrumentação , Tomografia por Emissão de Pósitrons/métodos , Contagem de Cintilação/instrumentação , Software , Tomografia Computadorizada por Raios X/métodos , Humanos , Modelos Biológicos
9.
IEEE Trans Med Imaging ; 37(11): 2526-2535, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29994248

RESUMO

A novel approach to tomographic data processing has been developed and evaluated using the Jagiellonian positron emission tomography scanner as an example. We propose a system in which there is no need for powerful, local to the scanner processing facility, capable to reconstruct images on the fly. Instead, we introduce a field programmable gate array system-on-chip platform connected directly to data streams coming from the scanner, which can perform event building, filtering, coincidence search, and region-of-response reconstruction by the programmable logic and visualization by the integrated processors. The platform significantly reduces data volume converting raw data to a list-mode representation, while generating visualization on the fly.


Assuntos
Interpretação de Imagem Assistida por Computador/instrumentação , Tomografia por Emissão de Pósitrons/instrumentação , Algoritmos , Desenho de Equipamento , Interpretação de Imagem Assistida por Computador/métodos , Tomografia por Emissão de Pósitrons/métodos
10.
J Immunol Res ; 2018: 1292404, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30003111

RESUMO

CD4+CD25highCD127low/-FoxP3+ regulatory T cells (Tregs) are currently under extensive investigation in childhood acute lymphoblastic leukemia (ALL) and in other human cancers. Usually, Treg cells maintain the immune cell homeostasis. This small subset of T cells has been, in fact, considered to be involved in the pathogenesis of autoimmune diseases and progression of acute and chronic leukemias. However, whether Treg dysregulation in CLL and ALL plays a key role or it rather represents a simple epiphenomenon is still a matter of debate. Treg cells have been proposed as a prognostic indicator of the clinical course of the disease and might also be used for targeted immune therapy. Our study revealed statistically higher percentage of Treg cells in the bone marrow than in peripheral blood in the group of 42 children with acute lymphoblastic leukemia. By analyzing Treg subpopulations, it was shown that only memory Tregs in contact with leukemic antigens showed statistically significant differences. We noticed a low negative correlation between Treg cells in the bone marrow and the percentage of blasts (R = -0.36) as well as a moderate correlation between Treg cells in the bone marrow and Hb level (R = +0.41) in peripheral blood before therapy. The number of peripheral blood blasts on day 8th correlates negatively (R = -0.36) with Tregs. Furthermore, statistical analysis revealed low negative correlation between the number of Tregs in the bone marrow and the minimal residual disease measured on day 15th, the percentage of blasts in the bone marrow and leukocytosis after 15 days of chemotherapy. These results indicate the influence of Tregs on the final therapeutic effect.


Assuntos
Antígenos CD/imunologia , Medula Óssea/imunologia , Fatores de Transcrição Forkhead/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Adolescente , Antígenos CD/sangue , Medula Óssea/patologia , Antígenos CD4/sangue , Antígenos CD4/imunologia , Criança , Pré-Escolar , Progressão da Doença , Feminino , Fatores de Transcrição Forkhead/sangue , Humanos , Imunofenotipagem , Lactente , Subunidade alfa de Receptor de Interleucina-2/sangue , Subunidade alfa de Receptor de Interleucina-2/imunologia , Subunidade alfa de Receptor de Interleucina-7/sangue , Subunidade alfa de Receptor de Interleucina-7/imunologia , Subpopulações de Linfócitos , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/sangue , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Prognóstico , Linfócitos T Reguladores/patologia
11.
Transplant Proc ; 50(6): 1625-1630, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30056871

RESUMO

Donor-recipient crossmatching for kidney transplantation is an obligatory step for the transplant work-up process. Attention is currently put on single bead assay (SBA) that enables virtual crossmatching. In contrast, methods developed for complement binding capacity are still not routinely established. We compared modified, cytolytic flow cytometry crossmatch (cFC-XM) with complement-dependent serological crossmatch (CDC-XM), SBA, and flow cytometry crossmatch (FC-XM) to verify whether newly developed techniques may be beneficial for transplant immunological matching. Also, the cutoff value for donor-specific alloantibodies levels currently used for virtual crossmatch was verified. Serum from 22 sensitized patients was crossmatched with surrogate donors by CDC-XM, FC-XM, and cFC-XM, while anti-HLA antibodies were measured by SBA. In all cases, virtual crossmatch was positive at 5000 mean fluorescence intensity cutoff. Among 22 tested sera with donor-specific alloantibodies above 5000 mean fluorescence intensity, the positive CDC-XM result was noted only in 41% of patients (n = 9), but positive FC-XM was noted in 86% (n = 19), and further lytic antibodies (cFC-XM) were confirmed in 27% of cases (n = 6). Our results suggest that donor-recipient immunological matching for kidney transplantation requires different methods to verify the importance of alloantibodies, and improvement in laboratory investigation is needed. This is especially important for immunized patients that have many types of alloantibodies and virtual crossmatching used as a tool for deceased donor allocation should balance between the likelihood of transplantation and risk of positive crossmatch result.


Assuntos
Tipagem e Reações Cruzadas Sanguíneas/métodos , Proteínas do Sistema Complemento/análise , Seleção do Doador/métodos , Isoanticorpos/sangue , Transplante de Rim , Proteínas do Sistema Complemento/imunologia , Feminino , Citometria de Fluxo/métodos , Antígenos HLA/imunologia , Humanos , Masculino , Valores de Referência
12.
Opt Lett ; 43(12): 2905-2908, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29905720

RESUMO

We present a Lyman-α laser developed for cooling trapped antihydrogen. The system is based on a pulsed Ti:sapphire laser operating at 729 nm that is frequency doubled using an LBO crystal and then frequency tripled in a Kr/Ar gas cell. After frequency conversion, this system produces up to 5.7 µW of average power at the Lyman-α wavelength. This laser is part of the ATRAP experiment at the antiproton decelerator in CERN.

13.
Artigo em Inglês | MEDLINE | ID: mdl-36937038

RESUMO

Background: Warm fresh whole blood (WFWB) is an ideal resuscitation fluid for exsanguinating patients but there are myriad logistic and infectious issues associated with its use. Cold whole blood (CWB) may be an acceptable alternative to the reconstituted whole blood (RWB), the current standard of care. A leukoreduction filter has been developed which maintains platelet count while eliminating white blood cells but its effect on platelet function is unknown. We hypothesize that CWB will retain an acceptable functional coagulation profile after filtration and over time. Study Design and Methods: WFWB and CWB samples were obtained from eight donors and four units of RWB were created. The quantitative and qualitative in vitro coagulation profiles of WFWB, RWB, and CWB over time were compared. Results: Filtration was successful at removing white blood cells (5.5 ± 1.2 vs. 0.3 ± 0.3 × 106/L) while retaining an adequate platelet count (172.0 ± 47.0 to 166.0 ± 42.3 × 109/L) and hemoglobin concentration (13.7 ± 0.5 vs. 13.0 ± 0.7 g/dL). Rotational Thromboelastography (ROTEM) results revealed a similar clotting time (CT) before and after filtration (64.9 ± 5.1 vs. 64.1 ± 6.8 s) but a decreased maximum clot firmness (MCF) (58.6 ± 4.2 vs. 54.9 ± 4.6 mm). Platelet aggregation decreased substantially (28.8 ± 6.7 vs. 9.3 ± 2.1 ohm) immediately after filtration. CWB function continued to diminish over time. Conclusion: CWB holds great promise as a surrogate for WFWB, but use of a platelet-sparing LR filter diminishes platelet function almost immediately after filtration.

14.
BMC Infect Dis ; 17(1): 328, 2017 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-28476105

RESUMO

BACKGROUND: Disseminated Histoplasmosis (DH) is a rare manifestation of Acquired Immune Deficiency Syndrome (AIDS) in European countries. Naso-maxillar osteolysis due to Histoplasma capsulatum var. capsulatum (Hcc) is unusual in endemic countries and has never been reported in European countries. Differential diagnoses such as malignant tumors, cocaine use, granulomatosis, vasculitis and infections are more frequently observed and could delay and/or bias the final diagnosis. CASE PRESENTATION: We report the case of an immunocompromised patient infected by Human Immunodeficiency Virus (HIV) with naso-maxillar histoplasmosis in a non-endemic country. Our aim is to describe the clinical presentation, the diagnostic and therapeutic issues. A 53-year-old woman, originated from Haiti, was admitted in 2016 for nasal deformation with alteration of general condition evolving for at least 6 months. HIV infection was diagnosed in 2006 and classified at AIDS stage in 2008 due to cytomegalovirus infection associated with pulmonary histoplasmosis. At admission, CD4 cell count was 9/mm3. Surgical biopsies were performed and ruled out differential or associated diagnoses. Mycological cultures identified Hcc and Blood Polymerase Chain Reaction (PCR) for Hcc was positive. The patient was given daily Amphothericin B liposomal infusion during 1 month. Hcc PCR became negative in the blood under treatment, and then oral switch by itraconazole was introduced. Antiretroviral treatment was reintroduced after a 3-week histoplasmosis treatment. Normalization of naso-maxillar mucosa enabled a palatal prosthesis. CONCLUSION: Naso-maxillar histoplasmosis is extremely rare; this is the first case ever reported in a non-endemic country. Differential diagnoses must be ruled out by conducting microbiologic tools and histological examinations on surgical biopsies. Early antifungal treatment should be initiated in order to prevent DH severe outcomes.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/etiologia , Histoplasmose/tratamento farmacológico , Histoplasmose/etiologia , Osteólise/etiologia , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Fármacos Anti-HIV/uso terapêutico , Antifúngicos/uso terapêutico , Contagem de Linfócito CD4 , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/etiologia , Diagnóstico Diferencial , Feminino , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Haiti , Histoplasmose/diagnóstico , Humanos , Hospedeiro Imunocomprometido , Itraconazol/uso terapêutico , Pneumopatias Fúngicas/diagnóstico , Pneumopatias Fúngicas/tratamento farmacológico , Pneumopatias Fúngicas/etiologia , Doenças Maxilares/tratamento farmacológico , Doenças Maxilares/etiologia , Doenças Maxilares/microbiologia , Pessoa de Meia-Idade , Osteólise/microbiologia
15.
Phys Med Biol ; 62(12): 5076-5097, 2017 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-28452337

RESUMO

In this paper we estimate the time resolution of the J-PET scanner built from plastic scintillators. We incorporate the method of signal processing using the Tikhonov regularization framework and the kernel density estimation method. We obtain simple, closed-form analytical formulae for time resolution. The proposed method is validated using signals registered by means of the single detection unit of the J-PET tomograph built from a 30 cm long plastic scintillator strip. It is shown that the experimental and theoretical results obtained for the J-PET scanner equipped with vacuum tube photomultipliers are consistent.


Assuntos
Tomografia por Emissão de Pósitrons/instrumentação , Contagem de Cintilação/instrumentação , Desenho de Equipamento , Humanos , Plásticos , Fatores de Tempo
16.
Artigo em Inglês | MEDLINE | ID: mdl-27547122

RESUMO

We present a study of the application of the Jagiellonian positron emission tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the [Formula: see text] decays with angular and energy resolution equal to [Formula: see text] and [Formula: see text], respectively. An order of magnitude shorter decay time of signals from plastic scintillators with respect to the inorganic crystals results not only in better timing properties crucial for the reduction of physical and instrumental background, but also suppresses significantly the pile-ups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.

17.
Phys Med Biol ; 61(5): 2025-47, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26895187

RESUMO

Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the [Formula: see text] configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the [Formula: see text] matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of [Formula: see text]0.170 ns for 15 cm axial field-of-view (AFOV) and [Formula: see text]0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.


Assuntos
Fótons , Plásticos/efeitos da radiação , Tomografia por Emissão de Pósitrons/métodos , Contagem de Cintilação/métodos , Contagem de Cintilação/instrumentação
19.
World J Surg ; 40(2): 447-55, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26566779

RESUMO

INTRODUCTION: Current National Comprehensive Cancer Network guidelines for Stages II and III rectal cancer recommend neoadjuvant chemoradiation followed by curative intent surgery and adjuvant chemotherapy. It is unclear whether therapies in addition to surgery are truly beneficial in elderly patients. Our aim was to compare the survival of patients over 80 with Stages II and III rectal cancer undergoing curative intent surgery with or without additional therapy. MATERIALS AND METHODS: The National Cancer Data Base (NCDB 2006-2011) was queried for patients over 80 with Stages II and III rectal cancer. The primary outcome was overall survival. Patients were stratified based upon therapy group. Univariate group comparisons were made. Unadjusted Kaplan-Meier and multivariable Cox proportional hazards modeling survival analyses were performed. RESULTS: The query yielded 3098 patients over 80 with Stage II (N = 1566) or Stage III (N = 1532) disease. Approximately, half of the patients received surgery only. Kaplan-Meier analysis showed improved survival for patients receiving neoadjuvant and/or adjuvant therapy in addition to surgery, but there was no significant difference between those that received guideline concordant care (GCC), neoadjuvant chemoradiation only, or post-operative chemotherapy only. Cox proportional hazard modeling identified age >90 and margin positivity as independent risk factors for decreased overall survival. CONCLUSION: Analysis of NCDB data for Stages II and III rectal cancer in patients over 80 shows a survival benefit of adjuvant and/or neoadjuvant therapy over surgery alone. There does not appear to be a difference in survival between patients who received neoadjuvant chemoradiation, post-resection adjuvant chemotherapy, or GCC.


Assuntos
Neoplasias Retais/patologia , Neoplasias Retais/terapia , Idoso de 80 Anos ou mais , Quimiorradioterapia Adjuvante/mortalidade , Quimioterapia Adjuvante/mortalidade , Bases de Dados Factuais , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Terapia Neoadjuvante/mortalidade , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Neoplasias Retais/mortalidade , Neoplasias Retais/cirurgia , Taxa de Sobrevida
20.
Eur Ann Otorhinolaryngol Head Neck Dis ; 132(6): 321-5, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26409827

RESUMO

OBJECTIVES: With medical improvements in pediatrics, the role of tracheotomy has evolved. The aim of this study was to specify the indications for and complications of tracheotomy performed on children in a teaching hospital containing a level-3 maternity department and pediatric intensive care unit. MATERIAL AND METHODS: A retrospective study was conducted in pediatric tracheotomies performed from 2004 to 2014. Indications, early and late complications and the number and timing of decannulations were collated. RESULTS: Fifty-seven patients were included. Tracheotomy was motivated by upper airway obstruction in 39 children (68%) (median age, 4.9 months) or the need for prolonged ventilation in 18 children (32%) (median age, 6 months). There were 4 early complications (7%) (2 decannulations, including 1 fatal; an obstructive plug, responsible for another death; and 1 pneumothorax during an EXIT procedure), and 15 secondary complications requiring further surgery (26%). Twenty-seven patients (47%) were decannulated, with a mean tracheotomy duration of 26 months. In 9 cases (33% of decannulations), persistence of tracheocutaneous fistula required surgical repair. CONCLUSION: Tracheotomy for infection is almost a thing of the past; tracheotomy for airway obstruction is also likely to decrease, thanks to medical treatment (for hemangioma) and surgical techniques (for congenital stenosis). Tracheotomy for prolonged ventilation, on the other hand, remains. Complications of tracheotomy in children are rare but potentially serious, requiring care in a specialized center within a multidisciplinary team with defined care protocols.


Assuntos
Traqueotomia , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos , Traqueotomia/efeitos adversos
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