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1.
Genes Immun ; 18(3): 176-183, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28794505

RESUMO

Tolerogenic dendritic cells (tolDCs) are assessed as immunomodulatory adjuvants to regulate autoimmunity. The underlying gene expression endorsing their regulatory features remains ill-defined. Using deep mRNA sequencing, we compared transcriptomes of 1,25-dihydroxyvitaminD3/dexametasone-modulated tolDCs with that of non-modulated mature inflammatory DCs (mDCs). Differentially expressed genes controlled cellular interactions, metabolic pathways and endorse tolDCs with the capacity to regulate cell activation through nutrient and signal deprivation, collectively gearing tolDCs into tolerogenic immune regulators. Gene expression differences correlated with protein expression, designating low CD86 and high CD52 on the cell surface as superior discriminators between tolDCs and mDCs. Of 37 candidate genes conferring risk to developing type 1 diabetes (T1D), 11 genes differentially expressed in tolDCs and mDCs regulated immune response and antigen-presenting activity. Differential-expressed transcripts of candidate risk loci for T1D suggest a role of these 'risk genes' in immune regulation, which targeting may modulate the genetic contribution to autoimmunity.


Assuntos
Autoimunidade/genética , Células Dendríticas/imunologia , Diabetes Mellitus Tipo 1/genética , Tolerância Imunológica/genética , Transcriptoma , Apresentação de Antígeno/genética , Antígeno B7-2/genética , Antígeno B7-2/metabolismo , Antígeno CD52/genética , Antígeno CD52/metabolismo , Calcitriol/farmacologia , Linhagem Celular , Células Cultivadas , Células Dendríticas/efeitos dos fármacos , Dexametasona/farmacologia , Diabetes Mellitus Tipo 1/imunologia , Humanos
2.
Br J Anaesth ; 118(3): 298-310, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28203792

RESUMO

Cardiac output (CO) measurement is crucial for the guidance of therapeutic decisions in critically ill and high-risk surgical patients. Newly developed completely non-invasive CO technologies are commercially available; however, their accuracy and precision have not recently been evaluated in a meta-analysis. We conducted a systematic search using PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science to review published data comparing CO measured by bolus thermodilution with commercially available non-invasive technologies including pulse wave transit time, non-invasive pulse contour analysis, thoracic electrical bioimpedance/bioreactance, and CO2 rebreathing. The non-invasive CO technology was considered acceptable if the pooled estimate of percentage error was <30%, as previously recommended. Using a random-effects model, sd, pooled mean bias, and mean percentage error were calculated. An I2 statistic was also used to evaluate the inter-study heterogeneity. A total of 37 studies (1543 patients) were included. Mean CO of both methods was 4.78 litres min−1. Bias was presented as the reference method minus the tested methods in 15 studies. Only six studies assessed the random error (repeatability) of the tested device. The overall random-effects pooled bias (limits of agreement) and the percentage error were −0,13 [−2.38 , 2.12] litres min−1 and 47%, respectively. Inter-study sensitivity heterogeneity was high (I2=83%, P<0.001). With a wide percentage error, completely non-invasive CO devices are not interchangeable with bolus thermodilution. Additional studies are warranted to demonstrate their role in improving the quality of care.


Assuntos
Débito Cardíaco , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Assistência Perioperatória/instrumentação , Assistência Perioperatória/métodos , Humanos , Reprodutibilidade dos Testes
3.
Dysphagia ; 32(2): 250-260, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27873090

RESUMO

Early and reliable screening for oropharyngeal dysphagia (OD) symptoms in at-risk populations is important and a crucial first stage in effective OD management. The Eating Assessment Tool (EAT-10) is a commonly utilized screening and outcome measure. To date, studies using classic test theory methodologies report good psychometric properties, but the EAT-10 has not been evaluated using item response theory (e.g., Rasch analysis). The aim of this multisite study was to evaluate the internal consistency and structural validity and conduct a preliminary investigation of the cross-cultural validity of the EAT-10; floor and ceiling effects were also checked. Participants involved 636 patients deemed at risk of OD, from outpatient clinics in Spain, Turkey, Sweden, and Italy. The EAT-10 and videofluoroscopic and/or fiberoptic endoscopic evaluation of swallowing were used to confirm OD diagnosis. Patients with esophageal dysphagia were excluded to ensure a homogenous sample. Rasch analysis was used to investigate person and item fit statistics, response scale, dimensionality of the scale, differential item functioning (DIF), and floor and ceiling effect. The results indicate that the EAT-10 has significant weaknesses in structural validity and internal consistency. There are both item redundancy and lack of easy and difficult items. The thresholds of the rating scale categories were disordered and gender, confirmed OD, and language, and comorbid diagnosis showed DIF on a number of items. DIF analysis of language showed preliminary evidence of problems with cross-cultural validation, and the measure showed a clear floor effect. The authors recommend redevelopment of the EAT-10 using Rasch analysis.


Assuntos
Transtornos de Deglutição/diagnóstico , Nível de Saúde , Inquéritos Epidemiológicos , Idoso , Idoso de 80 Anos ou mais , Cultura , Europa (Continente) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Reprodutibilidade dos Testes , Autorrelato
4.
Br J Anaesth ; 117(4): 442-449, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28077530

RESUMO

BACKGROUND: As 6% hydroxyethyl starch (HES) 130/0.40 or 130/0.42 can originate from different vegetable sources, they might have different clinical effects. The purpose of this prospective, randomized, double-blind controlled trial was to compare two balanced tetrastarch solutions, one maize-derived and one potato-derived, on perioperative blood loss in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). METHODS: We randomly assigned 118 patients undergoing elective cardiac surgery into two groups, to receive either a maize- or a potato-derived HES solution. Study fluids were administered perioperatively (including priming of CPB) until the second postoperative day (POD#2) using a goal directed algorithm. The primary outcome was calculated postoperative blood loss up to POD#2. Secondary outcomes included short-term incidence of acute kidney injury (AKI), and long-term effect (up to one yr) on renal function. RESULTS: Preoperative and intraoperative characteristics of the subjects were similar between groups. Similar volumes of HES were administered (1950 ml [1250-2325] for maize-HES and 2000 ml [1500-2700] for potato-HES; P=0.204). Calculated blood loss (504 ml [413-672] for maize-HES vs 530 ml [468-705] for potato-HES; P=0.107) and the need for blood components were not different between groups. The incidence of AKI was similar in both groups (P=0.111). Plasma creatinine concentration and glomerular filtration rates did vary over time, although changes were minimal. CONCLUSIONS: Under our study conditions, HES 130/0.4 or 130/0.42 raw material did not have a significant influence on perioperative blood loss. Moreover, we did not find any effect of tetrastarch raw material composition on short and long-term renal function. CLINICAL TRIAL REGISTRATION: EudraCT number: 2011-005920-16.


Assuntos
Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Derivados de Hidroxietil Amido/farmacologia , Hemorragia Pós-Operatória/epidemiologia , Injúria Renal Aguda/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ponte Cardiopulmonar , Creatinina/sangue , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
5.
Br J Anaesth ; 114(6): 886-92, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25690834

RESUMO

BACKGROUND: Goal directed fluid therapy (GDFT) has been shown to improve outcomes in moderate to high-risk surgery. However, most of the present GDFT protocols based on cardiac output optimization use invasive devices and the protocols may require significant practitioner attention and intervention to apply them accurately. The aim of this prospective pilot study was to evaluate the clinical feasibility of GDFT using a closed-loop fluid administration system with a non-invasive cardiac output monitoring device (Nexfin™, BMEYE, Amsterdam, Netherlands). METHODS: Patients scheduled for elective moderate risk surgery under general anaesthesia were enrolled. The primary anaesthesia team managing the case selected GDFT targets using the controller interface and all patients received a baseline 3 ml kg(-1) h(-1) crystalloid infusion. Colloid solutions were delivered by the closed-loop system for intravascular volume expansion using data from the Nexfin™ monitor. Compliance with GDFT management was defined as acceptable when a patient spent more than 85% of the surgery time in a preload independent state (defined as pulse pressure variation <13%) or when average cardiac index during surgery was >2.5 litre min(-1) m(-2). RESULTS: A total of 13 patients were included in the study group. All patients met the established criteria for delivery of GDFT for greater than 85% of case time. The median length of stay in the hospital was 5 [3-6] days. CONCLUSION: In this pilot study, GDFT management using the closed-loop fluid administration system with a non-invasive CO monitoring device was feasible and maintained a high rate of protocol compliance. CLINICAL TRIAL REGISTRATION: NCT02020863.


Assuntos
Débito Cardíaco/fisiologia , Hidratação/métodos , Monitorização Intraoperatória/métodos , Idoso , Anestesia Geral , Perda Sanguínea Cirúrgica , Estudos de Viabilidade , Feminino , Hidratação/instrumentação , Fidelidade a Diretrizes/estatística & dados numéricos , Hemodinâmica/fisiologia , Humanos , Longevidade , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/instrumentação , Monitorização Fisiológica/métodos , Fotopletismografia/instrumentação , Fotopletismografia/métodos , Projetos Piloto , Estudos Prospectivos , Volume Sistólico/fisiologia
6.
Support Care Cancer ; 20(11): 3013-7, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22875415

RESUMO

PURPOSE: The aim of our study was to evaluate the frequency of "occult" bacteremia/fungemia as well as the diversity of pathogens involved in hematology patients treated with corticosteroids. METHODS: Daily surveillance blood cultures were taken from patients treated with corticosteroids as part of their intensive chemotherapy or during graft-versus-host disease following hematopoietic stem cell transplantation during a 3-year period (2006-2009). We reviewed the frequency of occult bacteremia/fungemia as well as the pathogens involved. RESULTS: During the 3-year period, 3,821 bottles were cultured from 215 patients and 4.9 % of the bottles tested were positive. Surveillance blood cultures revealed bloodstream infection in 24 % of the patients (definite bloodstream infection in 16 %). Seventy-five percent of patients were still afebrile when microorganisms were detected. The main risk group was acute lymphocytic leukemia patients undergoing remission induction chemotherapy. The pathogens cultured most frequently were coagulase-negative staphylococci, enterococci, Escherichia coli, and Pseudomonas aeruginosa. CONCLUSIONS: A high incidence of occult bacteremia was detected by surveillance blood cultures. Further studies are needed to evaluate if a strategy based on surveillance blood cultures can reduce mortality related to bloodstream infections.


Assuntos
Bacteriemia/epidemiologia , Fungemia/epidemiologia , Glucocorticoides/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Técnicas Bacteriológicas , Criança , Pré-Escolar , Feminino , Fungemia/diagnóstico , Fungemia/microbiologia , Glucocorticoides/uso terapêutico , Doença Enxerto-Hospedeiro/tratamento farmacológico , Neoplasias Hematológicas/patologia , Neoplasias Hematológicas/terapia , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Micologia/métodos , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
7.
Children (Basel) ; 9(7)2022 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-35884000

RESUMO

Apophyseal avulsions of the rectus femorus tendon (RFT) at the anterior inferior iliac spine (AIIS) can occur in adolescents, often while performing soccer. Patient-reported outcomes (PROMs) and time to return to sport of these patients are relatively unknown. Therefore, the aim of this study was to assess the PROMs and return to sports of patients with AIIS avulsions and compare the results with those reported in the literature. This is a case series of seven consecutive patients presenting at our hospital between 2018 and 2020 with an apophyseal avulsion of the RFT from the AIIS. The patients were assessed with use of the WOMAC and Tegner scores and return to sports was evaluated. All patients were male soccer players (median age 13 years; range, 12-17). They were all initially treated non-operatively. One of the patients subsequently needed excision surgery of a heterotopic ossification because of non-transient hip impingement. All other patients recovered after a period of relative rest. Median time to return to sports was 2.5 months (range, 2-3). At a median follow-up of 33 months (range, 18-45), the WOMAC (median, 100; range, 91-100) and Tegner scores (median, 9; range, 5-9) were high. In accordance with the existing literature, most patients with apophyseal avulsions of the AIIS recover well with non-operative treatment. However, the avulsion can lead to hip impingement due to heterotopic ossifications possibly needing surgical excision. Sport resumption is achievable after 2-3 months, and patient-reported outcomes are highly satisfactory in the long term.

8.
J Exp Med ; 193(1): 73-88, 2001 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11136822

RESUMO

We report the efficient identification of four human histocompatibility leukocyte antigen (HLA)-A(*)0201-presented cytotoxic T lymphocyte (CTL) epitopes in the tumor-associated antigen PRAME using an improved "reverse immunology" strategy. Next to motif-based HLA-A(*)0201 binding prediction and actual binding and stability assays, analysis of in vitro proteasome-mediated digestions of polypeptides encompassing candidate epitopes was incorporated in the epitope prediction procedure. Proteasome cleavage pattern analysis, in particular determination of correct COOH-terminal cleavage of the putative epitope, allows a far more accurate and selective prediction of CTL epitopes. Only 4 of 19 high affinity HLA-A(*)0201 binding peptides (21%) were found to be efficiently generated by the proteasome in vitro. This approach avoids laborious CTL response inductions against high affinity binding peptides that are not processed and limits the number of peptides to be assayed for binding. CTL clones induced against the four identified epitopes (VLDGLDVLL, PRA(100-108); SLYSFPEPEA, PRA(142-151); ALYVDSLFFL, PRA(300-309); and SLLQHLIGL, PRA(425-433)) lysed melanoma, renal cell carcinoma, lung carcinoma, and mammary carcinoma cell lines expressing PRAME and HLA-A(*)0201. This indicates that these epitopes are expressed on cancer cells of diverse histologic origin, making them attractive targets for immunotherapy of cancer.


Assuntos
Apresentação de Antígeno , Antígenos de Neoplasias/metabolismo , Cisteína Endopeptidases/metabolismo , Antígenos HLA-A/metabolismo , Complexos Multienzimáticos/metabolismo , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Antígenos de Neoplasias/genética , Sequência de Bases , Linhagem Celular Transformada , Citotoxicidade Imunológica , Primers do DNA/genética , Epitopos/genética , Epitopos/metabolismo , Humanos , Dados de Sequência Molecular , Complexo de Endopeptidases do Proteassoma , Ligação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Células Tumorais Cultivadas
9.
Ned Tijdschr Geneeskd ; 1632019 10 24.
Artigo em Holandês | MEDLINE | ID: mdl-31682088

RESUMO

A limping gait pattern in a child is a red flag for every physician until proven otherwise. Among the most common causes are coxitis fugax, infection (septic arthritis, osteomyelitis), Perthes disease, and slipped capital femoral epiphysis, depending on the age of the patient. A high index of suspicion is required because clinical findings are often subtle, and the diagnosis may be present even if initial radiographs are negative. A missed or delayed diagnosis may have devastating consequences. Therefore, this paper describes the main characteristics of different causes of a limping child, based on four typical cases. Tools are provided to recognize each diagnosis. Early referral to a paediatric orthopaedic surgeon is recommended.


Assuntos
Doença de Legg-Calve-Perthes/diagnóstico , Osteomielite/diagnóstico , Escorregamento das Epífises Proximais do Fêmur/diagnóstico , Criança , Diagnóstico Diferencial , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Radiografia
11.
Phys Med Biol ; 62(14): 5840-5860, 2017 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-28467321

RESUMO

The aim of this work is to develop and investigate an inverse treatment planning process (TPP) for mixed beam radiotherapy (MBRT) capable of performing simultaneous optimization of photon and electron apertures. A simulated annealing based direct aperture optimization (DAO) is implemented to perform simultaneous optimization of photon and electron apertures, both shaped with the photon multileaf collimator (pMLC). Validated beam models are used as input for Monte Carlo dose calculations. Consideration of photon pMLC transmission during DAO and a weight re-optimization of the apertures after deliverable dose calculation are utilized to efficiently reduce the differences between optimized and deliverable dose distributions. The TPP for MBRT is evaluated for an academic situation with a superficial and an enlarged PTV in the depth, a left chest wall case including the internal mammary chain and a squamous cell carcinoma case. Deliverable dose distributions of MBRT plans are compared to those of modulated electron radiotherapy (MERT), photon IMRT and if available to those of clinical VMAT plans. The generated MBRT plans dosimetrically outperform the MERT, photon IMRT and VMAT plans for all investigated situations. For the clinical cases of the left chest wall and the squamous cell carcinoma, the MBRT plans cover the PTV similarly or more homogeneously than the VMAT plans, while OARs are spared considerably better with average reductions of the mean dose to parallel OARs and D 2% to serial OARs by 54% and 26%, respectively. Moreover, the low dose bath expressed as V 10% to normal tissue is substantially reduced by up to 45% compared to the VMAT plans. A TPP for MBRT including simultaneous optimization is successfully implemented and the dosimetric superiority of MBRT plans over MERT, photon IMRT and VMAT plans is demonstrated for academic and clinical situations including superficial targets with and without deep-seated part.


Assuntos
Elétrons , Fótons/uso terapêutico , Radioterapia de Intensidade Modulada/métodos , Humanos , Método de Monte Carlo , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Fatores de Tempo
12.
J Immunol Methods ; 144(2): 203-13, 1991 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-1960417

RESUMO

The immunospot (ELISPOT) assay has proven to be an efficient and sensitive method for the enumeration of single cells secreting antibodies or cytokines. Here we show that the generation of interferon-gamma producing cells (IFN-gamma pc) in rat spleen cell cultures stimulated with concanavalin A (ConA) is dose-dependently inhibited by a wide variety of immunosuppressants such as cyclosporin A, FK506, hydrocortisone, dexamethasone, azathioprine and ART-18, a monoclonal antibody (mAb) with established immunosuppressive activity in organ transplantation and autoimmunity. The minimal inhibitory concentration (m.i.c.) correlated well with the reported m.i.c. in the mixed lymphocyte reaction (MLR) assay and the therapeutically effective plasma levels in vivo. Our data indicate that the IFN-gamma-specific immunospot assay is a powerful tool for determining the potency of immunosuppressive agents in vitro and provides a simple and accurate method for screening large numbers of agents with suspected immunosuppressive properties. The assay may additionally prove to be of value for determining the therapeutically effective doses of immunosuppressants that should be administered in vivo.


Assuntos
Imunossupressores/farmacologia , Interferon gama/biossíntese , Linfócitos T/efeitos dos fármacos , Animais , Anticorpos Monoclonais/imunologia , Células Cultivadas , Feminino , Antígenos de Histocompatibilidade Classe II/análise , Interleucina-2/biossíntese , Interleucina-2/farmacologia , Metotrexato/farmacologia , Ratos , Ratos Endogâmicos , Linfócitos T/metabolismo
13.
Clin Neurol Neurosurg ; 102(3): 176-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10996719

RESUMO

Pachymeningitis luetica is extremely rare in developed countries. We describe a 41-year-old male patient with pachymeningitis luetica, multiple ischaemic infarctions, and severe hydrocephalus. The delay in making the diagnosis contributed to patient's death. Rapid diagnosis is essential on the slightest suspicion of an infection by Treponema pallidum, because timely treatment with antibiotics is effective.


Assuntos
Encéfalo/microbiologia , Erros de Diagnóstico , Hidrocefalia/microbiologia , Neurossífilis/diagnóstico , Treponema pallidum/isolamento & purificação , Adulto , Encéfalo/patologia , Encefalopatias/diagnóstico , Diagnóstico Diferencial , Evolução Fatal , Humanos , Hidrocefalia/cirurgia , Masculino , Neurossífilis/microbiologia , Tabes Dorsal/complicações , Tabes Dorsal/diagnóstico , Derivação Ventriculoperitoneal/efeitos adversos
14.
Nucl Med Commun ; 16(8): 703-5, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7491185

RESUMO

Multiple sclerosis (MS) is predominantly a progressive immune-mediated disease of the white matter in the brain. We used single photon emission tomography (SPET) and cobalt-57 (57Co) as a calcium (Ca) analogue to visualize brain tissue damage, based on the fact that Ca influx occurs in both cell death and T-lymphocyte activation in MS. The aim of this study was to determine if 57Co-SPET detects MS lesions and, if so, to compare this with clinical data on the patient. Five MS patients underwent neurological examination including Expanded Disability Status Scale (EDSS) assessment and 57Co-SPET, using a single-headed camera. All available data were compared. The lesions were recognized as areas of increased signal intensity, although the poor count rate did not allow any statistical quantification. A relationship between one 57Co-SPET parameter (cobalt plaque load) and EDSS was demonstrated. In conclusion, this pilot study suggests that 57Co-SPET using a single-headed camera is not an appropriate imaging modality in MS. To obtain a more favourable signal-to-noise ratio, the use of a multi-headed camera, the administration of a higher activity of 57Co and a longer acquisition time are recommended. Validation of this method among a larger group of patients and a comparison with healthy volunteers is needed.


Assuntos
Encéfalo/diagnóstico por imagem , Radioisótopos de Cobalto , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/fisiopatologia , Tomografia Computadorizada de Emissão de Fóton Único , Encéfalo/patologia , Cálcio/metabolismo , Morte Celular , Radioisótopos de Cobalto/farmacocinética , Feminino , Humanos , Masculino , Projetos Piloto
15.
Ned Tijdschr Geneeskd ; 147(30): 1470-2, 2003 Jul 26.
Artigo em Holandês | MEDLINE | ID: mdl-12908351

RESUMO

A 41-year-old woman was admitted to the hospital with meningitis caused by Listeria monocytogenes. Because of her Crohn's disease she used prednisolone and azathioprine. Two weeks before presenting with meningitis, infliximab had been given as the other immunosuppressant drugs had no effect. This tumour necrosis factor alpha (TNF alpha) blocking agent is known to increase the risk of opportunistic infections. This is the first Dutch patient described with meningitis caused by L. monocytogenes after treatment with infliximab. She recovered after antibiotic therapy. When antibiotic treatment is chosen, the possibility of opportunistic infections in patients who use infliximab concurrently with other immunosuppressant drugs should be taken into account.


Assuntos
Anticorpos Monoclonais/efeitos adversos , Fármacos Gastrointestinais/efeitos adversos , Meningite por Listeria/induzido quimicamente , Infecções Oportunistas/induzido quimicamente , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Adulto , Anticorpos Monoclonais/uso terapêutico , Doença de Crohn/tratamento farmacológico , Feminino , Fármacos Gastrointestinais/uso terapêutico , Humanos , Infliximab , Listeria monocytogenes/crescimento & desenvolvimento , Meningite por Listeria/imunologia , Infecções Oportunistas/imunologia , Fator de Necrose Tumoral alfa/imunologia
16.
Tijdschr Diergeneeskd ; 117(6): 165-8, 1992 Mar 15.
Artigo em Holandês | MEDLINE | ID: mdl-1549831

RESUMO

Five of eight meat cattle died suddenly without showing prior symptoms of disease. The sudden death occurred in connection with the feeding of mouldy tulip bulbs. A short review is given of the use of flower bulbs as cattle feed, the use of herbicides/fungicides in bulb cultivation, and the relevant legislation. Several toxicological aspects that should be taken into consideration when flower bulbs are used as cattle feed are discussed. Both the Central Veterinary Institute and the State Institute for Public Health and Environmental Hygiene showed, in experiments with mice, the presence of a toxin in extracts of the mouldy tulip bulbs. This toxin is probably produced by moulds present in the tulip bulbs. The death of the animals was probably caused by an as yet unidentified mycotoxin.


Assuntos
Ração Animal/efeitos adversos , Doenças dos Bovinos/induzido quimicamente , Micotoxicose/veterinária , Micotoxinas/toxicidade , Animais , Bovinos , Feminino , Masculino , Micotoxicose/etiologia , Plantas Tóxicas
17.
Phys Med Biol ; 59(16): 4697-722, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-25082795

RESUMO

The comparison of radiotherapy techniques regarding secondary cancer risk has yielded contradictory results possibly stemming from the many different approaches used to estimate risk. The purpose of this study was to make a comprehensive evaluation of different available risk models applied to detailed whole-body dose distributions computed by Monte Carlo for various breast radiotherapy techniques including conventional open tangents, 3D conformal wedged tangents and hybrid intensity modulated radiation therapy (IMRT). First, organ-specific linear risk models developed by the International Commission on Radiological Protection (ICRP) and the Biological Effects of Ionizing Radiation (BEIR) VII committee were applied to mean doses for remote organs only and all solid organs. Then, different general non-linear risk models were applied to the whole body dose distribution. Finally, organ-specific non-linear risk models for the lung and breast were used to assess the secondary cancer risk for these two specific organs. A total of 32 different calculated absolute risks resulted in a broad range of values (between 0.1% and 48.5%) underlying the large uncertainties in absolute risk calculation. The ratio of risk between two techniques has often been proposed as a more robust assessment of risk than the absolute risk. We found that the ratio of risk between two techniques could also vary substantially considering the different approaches to risk estimation. Sometimes the ratio of risk between two techniques would range between values smaller and larger than one, which then translates into inconsistent results on the potential higher risk of one technique compared to another. We found however that the hybrid IMRT technique resulted in a systematic reduction of risk compared to the other techniques investigated even though the magnitude of this reduction varied substantially with the different approaches investigated. Based on the epidemiological data available, a reasonable approach to risk estimation would be to use organ-specific non-linear risk models applied to the dose distributions of organs within or near the treatment fields (lungs and contralateral breast in the case of breast radiotherapy) as the majority of radiation-induced secondary cancers are found in the beam-bordering regions.


Assuntos
Neoplasias da Mama/radioterapia , Modelos Estatísticos , Método de Monte Carlo , Neoplasias Induzidas por Radiação/etiologia , Segunda Neoplasia Primária/etiologia , Doses de Radiação , Radioterapia de Intensidade Modulada/efeitos adversos , Neoplasias da Mama/diagnóstico por imagem , Humanos , Modelos Lineares , Dinâmica não Linear , Imagens de Fantasmas , Proteção Radiológica , Dosagem Radioterapêutica , Medição de Risco , Tomografia Computadorizada por Raios X , Imagem Corporal Total
18.
Med Phys ; 41(12): 121711, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25471958

RESUMO

PURPOSE: A beamlet based direct aperture optimization (DAO) for modulated electron radiotherapy (MERT) using photon multileaf collimator (pMLC) shaped electron fields is developed and investigated. METHODS: The Swiss Monte Carlo Plan (SMCP) allows the calculation of dose distributions for pMLC shaped electron beams. SMCP is interfaced with the Eclipse TPS (Varian Medical Systems, Palo Alto, CA) which can thus be included into the inverse treatment planning process for MERT. This process starts with the import of a CT-scan into Eclipse, the contouring of the target and the organs at risk (OARs), and the choice of the initial electron beam directions. For each electron beam, the number of apertures, their energy, and initial shape are defined. Furthermore, the DAO requires dose-volume constraints for the structures contoured. In order to carry out the DAO efficiently, the initial electron beams are divided into a grid of beamlets. For each of those, the dose distribution is precalculated using a modified electron beam model, resulting in a dose list for each beamlet and energy. Then the DAO is carried out, leading to a set of optimal apertures and corresponding weights. These optimal apertures are now converted into pMLC shaped segments and the dose calculation for each segment is performed. For these dose distributions, a weight optimization process is launched in order to minimize the differences between the dose distribution using the optimal apertures and the pMLC segments. Finally, a deliverable dose distribution for the MERT plan is obtained and loaded back into Eclipse for evaluation. For an idealized water phantom geometry, a MERT treatment plan is created and compared to the plan obtained using a previously developed forward planning strategy. Further, MERT treatment plans for three clinical situations (breast, chest wall, and parotid metastasis of a squamous cell skin carcinoma) are created using the developed inverse planning strategy. The MERT plans are compared to clinical standard treatment plans using photon beams and the differences between the optimal and the deliverable dose distributions are determined. RESULTS: For the idealized water phantom geometry, the inversely optimized MERT plan is able to obtain the same PTV coverage, but with an improved OAR sparing compared to the forwardly optimized plan. Regarding the right-sided breast case, the MERT plan is able to reduce the lung volume receiving more than 30% of the prescribed dose and the mean lung dose compared to the standard plan. However, the standard plan leads to a better homogeneity within the CTV. The results for the left-sided thorax wall are similar but also the dose to the heart is reduced comparing MERT to the standard treatment plan. For the parotid case, MERT leads to lower doses for almost all OARs but to a less homogeneous dose distribution for the PTV when compared to a standard plan. For all cases, the weight optimization successfully minimized the differences between the optimal and the deliverable dose distribution. CONCLUSIONS: A beamlet based DAO using multiple beam angles is implemented and successfully tested for an idealized water phantom geometry and clinical situations.


Assuntos
Neoplasias/radioterapia , Radioterapia de Intensidade Modulada/métodos , Fenômenos Biofísicos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia , Feminino , Humanos , Método de Monte Carlo , Neoplasias/diagnóstico por imagem , Órgãos em Risco , Neoplasias Parotídeas/diagnóstico por imagem , Neoplasias Parotídeas/radioterapia , Neoplasias Parotídeas/secundário , Imagens de Fantasmas , Fótons/uso terapêutico , Radiografia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia de Alta Energia , Radioterapia de Intensidade Modulada/estatística & dados numéricos , Neoplasias Torácicas/diagnóstico por imagem , Neoplasias Torácicas/radioterapia
19.
Phys Med Biol ; 56(16): 5131-51, 2011 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-21775792

RESUMO

Second cancer risk assessment for radiotherapy is controversial due to the large uncertainties of the dose-response relationship. This could be improved by a better assessment of the peripheral doses to healthy organs in future epidemiological studies. In this framework, we developed a simple Monte Carlo (MC) model of the Siemens Primus 6 MV linac for both open and wedged fields that we then validated with dose profiles measured in a water tank up to 30 cm from the central axis. The differences between the measured and calculated doses were comparable to other more complex MC models and never exceeded 50%. We then compared our simple MC model with the peripheral dose profiles of five different linacs with different collimation systems. We found that the peripheral dose between two linacs could differ up to a factor of 9 for small fields (5 × 5 cm2) and up to a factor of 10 for wedged fields. Considering that an uncertainty of 50% in dose estimation could be acceptable in the context of risk assessment, the MC model can be used as a generic model for large open fields (≥10 × 10 cm2) only. The uncertainties in peripheral doses should be considered in future epidemiological studies when designing the width of the dose bins to stratify the risk as a function of the dose.


Assuntos
Neoplasias Induzidas por Radiação/etiologia , Segunda Neoplasia Primária/etiologia , Doses de Radiação , Medição de Risco/métodos , Relação Dose-Resposta à Radiação , Humanos , Método de Monte Carlo , Planejamento da Radioterapia Assistida por Computador , Reprodutibilidade dos Testes , Incerteza
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