Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 280
Filtrar
1.
Lung Cancer ; 192: 107823, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38763103

RESUMO

BACKGROUND: There is a paucity of information about the characteristics, treatment patterns, and outcomes of non-small cell lung cancer (NSCLC) patients with single organ metastasis (SOM). METHODS: This retrospective cohort study includes all patients with a diagnosis of stage IV NSCLC diagnosed from 2014 to 2016 and treated at Princess Margaret Cancer Centre. We compared baseline characteristics and patterns of metastatic sites between patients with SOM versus multiple (M)OM. Additionally, we identified treatment modalities and outcomes for patients with SOM. Cox multivariable models (MVA) were utilized to evaluate differences in overall survival (OS) between the SOM and MOM cohorts. RESULTS: Of 893 pts analyzed, 457 (51 %) had SOM, while 436 (49 %) had MOM at initial diagnosis. Demographics were comparable between the two groups. Brain was the most common site of metastasis for SOM patients. When compared to the MOM group, the SOM group had lower percentages of liver and adrenal metastases. Amongst SOM patients, 54 % received single modality treatment, and 20 % did not receive any treatment for their SOM. In MVA, patients with liver (HR 2.4), bone (HR 1.8), and pleural (HR 1.7) metastasis as their SOM site had the worst outcomes, with median OS of 6.8 months, 12.1 months, and 13.0 months respectively. Patients with SOM had a significantly improved median OS compared to those with MOM (15.9 months vs. 10.6 months; HR 0.56, 95 % CI 0.47-0.66, p < 0.001). CONCLUSION: In NSCLC patients who presented with SOM, survival correlated with the initial organ involved and was better overall compared to patients with MOM. SOM NSCLC may benefit from specific management strategies and SOM patients could be considered as a specific subgroup for survival analyses in observational and non-randomized interventional studies. In clinical trials, SOM can be considered as a stratification factor in the future.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/terapia , Estudos Retrospectivos , Feminino , Masculino , Idoso , Pessoa de Meia-Idade , Canadá/epidemiologia , Resultado do Tratamento , Metástase Neoplásica , Estadiamento de Neoplasias , Terapia Combinada
2.
Curr Oncol ; 27(6): e552-e559, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33380870

RESUMO

Background: Tyrosine kinase inhibitors (tkis) have dramatically improved the survival of patients with ALK-rearranged (ALK+) non-small-cell lung cancer (nsclc). Clinical trial data can generally compare drugs in a pair-wise fashion. Real-world collection of health utility data, symptoms, and toxicities allows for the direct comparison between multiple tki therapies in the population with ALK+ nsclc. Methods: In a prospective cohort study, outpatients with ALK+ recruited between 2014 and 2018, treated with a variety of tkis, were assessed every 3 months for clinico-demographic, patient-reported symptom and toxicity data and EQ-5D-derived health utility scores (hus). Results: In 499 longitudinal encounters of 76 patients with ALK+ nsclc, each tki had stable longitudinal hus when disease was controlled, even after months to years: the mean overall hus for each tki ranged from 0.805 to 0.858, and longitudinally from 0.774 to 0.912, with higher values associated with second- or third-generation tkis of alectinib, brigatinib, and lorlatinib. Disease progression was associated with a mean hus decrease of 0.065 (95% confidence interval: 0.02 to 0.11). Health utility scores were inversely correlated to multiple symptoms or toxicities: rho values ranged from -0.094 to -0.557. Fewer symptoms and toxicities were associated with the second- and third-generation tkis compared with crizotinib. In multivariable analysis, only stable disease state and baseline Eastern Cooperative Oncology Group performance status were associated with improved hus. Conclusions: There was no significant decrease in hus when patients with ALK+ disease were treated longitudinally with each tki, as long as patients were clinically stable. Alectinib, brigatinib, and lorlatinib had the best toxicity profiles and exhibited high mean hus longitudinally in the real-world setting.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Quinase do Linfoma Anaplásico/genética , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Estudos Prospectivos , Inibidores de Proteínas Quinases/efeitos adversos
3.
Curr Oncol ; 26(6): e733-e741, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31896943

RESUMO

Background: We assessed whether the presence and severity of common cancer symptoms are associated with the health utility score (hus) generated from the EQ-5D (EuroQol Research Foundation, Rotterdam, Netherlands) in patients with cancer and evaluated whether it is possible pragmatically to integrate routine hus and symptom evaluation in our cancer population. Methods: Adult outpatients at Princess Margaret Cancer Centre with any cancer were surveyed cross-sectionally using the Edmonton Symptom Assessment System (esas) and the EQ-5D-3L, and results were compared using Spearman correlation coefficients and regression analyses. Results: Of 764 patients analyzed, 27% had incurable disease. We observed mild-to-moderate correlations between each esas symptom score and the hus (Spearman coefficients: -0.204 to -0.416; p < 0.0001 for each comparison), with the strongest associations being those for pain (R = -0.416), tiredness (R = -0.387), and depression (R =-0.354). Multivariable analyses identified pain and depression as highly associated (both p < 0.0001) and tiredness as associated (p = 0.03) with the hus. The ability of the esas to predict the hus was low, at 0.25. However, by mapping esas pain, anxiety, and depression scores to the corresponding EQ-5D questions, we could derive the hus using partial esas data, with Spearman correlations of 0.83-0.91 in comparisons with direct EQ-5D measurement of the hus. Conclusions: The hus derived from the EQ-5D-3L is associated with all major cancer symptoms as captured by the esas. The esas scores alone could not predict EQ-5D scores with high accuracy. However, esas-derived questions assessing the same domains as the EQ-5D-3L questions could be mapped to their corresponding EQ-5D questions to generate the hus, with high correlation to the directly measured hus. That finding suggests a potential approach to integrating routine symptom and hus evaluations after confirmatory studies.


Assuntos
Neoplasias , Qualidade de Vida , Avaliação de Sintomas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ansiedade , Depressão , Fadiga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor , Medidas de Resultados Relatados pelo Paciente , Inquéritos e Questionários , Adulto Jovem
4.
Dis Esophagus ; 31(12)2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29905764

RESUMO

Esophageal cancer and its treatment can cause serious morbidity/toxicity. These effects on health-related quality of life (HRQOL) can be measured using disease-specific scales such as FACT-E, generic scales such as EQ-5D-3L, or through symptoms. In a two-year cross-sectional study, we compared HRQOL across esophageal cancer patients treated in an ambulatory clinic and across multiple disease states, among patients with all stages of esophageal cancer. Consenting patients completed FACT-E, EQ-5D, a visual analog scale, and patient reported (PR)-ECOG. Symptom complexes were constructed from FACT-E domains. Responses were categorized by disease state: pre-, during, and post-treatment, surveillance, progression, and palliative chemotherapy. Spearman correlation and multivariable linear regression characterized these associations. In total, 199 patients completed 317 questionnaires. Mean FACT-E and subscale scores dropped from baseline through treatment and recovered during post-treatment surveillance (P < 0.001); EQ-5D health utility scores (HUS) displayed a similar pattern but with smaller differences (P = 0.07), and with evidence of ceiling effect. Among patients with stage II/III esophageal cancer, mean EQ-5D HUS varied across disease states (P < 0.001), along with FACT-E and subscales (P < 0.001). Among patients with advanced disease, there was no significant difference between baseline and on-treatment total scores, but improved esophageal cancer-specific scales were noted (P = 0.003). Strong correlation was observed between EQ-5D and FACT-E (R = 0.73), along with physical and functional subscales. In addition, the association between FACT-E and EQ-5D HUS was maintained in a multivariable model (P < 0.001). We interpret these results to suggest that in a real-world clinic setting, FACT-E, EQ-5D HUS, and symptoms were strongly correlated. Most HRQOL and symptom parameters suggested that patients had worse HRQOL and symptoms during curative therapy, but recovered well afterwards. In contrast, palliative chemotherapy had a neutral to positive impact on HRQOL/symptoms when compared to their baseline pre-treatment state.


Assuntos
Neoplasias Esofágicas/diagnóstico , Nível de Saúde , Qualidade de Vida , Índice de Gravidade de Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estatísticas não Paramétricas , Inquéritos e Questionários
5.
Curr Oncol ; 24(3): 161-167, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28680275

RESUMO

BACKGROUND: Personal health information, including diagnoses and hospital admissions, is routinely collected in administrative databases. Patients enrolling on clinical trials consent to separate collection and storage of their personal health information. We evaluated patient preferences for linking long-term data from administrative databases with clinical trials. METHODS: Adults with cancer attending outpatient clinics at 3 Ontario hospitals were surveyed about their willingness, when faced with the hypothetical scenario of participating in a clinical trial, to provide potentially identifying information such as initials and date of birth to facilitate long-term research access to normally deidentified publicly collected databases. RESULTS: Of 569 patients surveyed, 335 (59%) were women, 452 (79%) were white, 385 (68%) had a post-secondary education, and 386 (68%) had never participated in a clinical trial. Median age in the group was 59 years. Most participants (93%, cohort 1) would allow long-term access to their information and allow personal information to be used to match clinical trial with administrative data. At the time of clinical trial closure, two thirds of participants (68%, cohort 2) preferred to make additional clinical information available through linkage with administrative databases, and 8 (9%) preferred to have no further information made available to researchers. No significant differences were found in the subset of patients who were part of a clinical trial and those who had never participated (p = 0.65). INTERPRETATION: Almost all patients would allow a clinical trial research team to access their confidential information, providing a more comprehensive assessment of an intervention's long-term risks and benefits.

6.
Dis Esophagus ; 30(2): 1-7, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-26822871

RESUMO

Gastroesophageal reflux disease (GERD) may lead to Barrett's esophagus (BE). Previously, a large genome-wide association study found two germline markers to be associated with BE, FOXF1 rs9936833 (C allele) and MHC rs9257809 (A allele). This study evaluated whether these two polymorphisms are associated with gastroesphageal acid reflux as measured by 24-hour pH testing. Patients with acid reflux symptoms referred for esophageal manometry and 24-hour pH monitoring at University Health Network (Toronto, ON) were enrolled. DNA extracted from blood was genotyped using a Taqman Polymerase Chain Reaction (PCR) assay. DeMeester scores of ≥14.7 or prior evidence of reflux esophagitis on endoscopy defined individuals with esophageal acid reflux. Logistic regression analysis, adjusted for clinical risk factors, was used to calculate odds ratios with 95% confidence intervals for each polymorphism in relation to the presence of acid reflux. Of 182 patients, the median age was 50 years and 62% were female; 95 (52%) met the definition of GERD. In the multivariable analysis, both FOXF1 rs9936833 (OR = 1.82; 95%CI: 1.12-2.96; P = 0.02) and MHC rs9257809 (OR = 9.36; 95%CI: 2.92-29.99; P < 0.001) remained significantly associated with presence of acid reflux. When both polymorphisms were placed in the same model, the adjusted ORs were 2.10 (95%CI: 1.24-3.53; P = 0.005) and 10.95 (95%CI: 3.32-36.09; P < 0.001), respectively. The association for risk allele C in FOXF1 rs9936833 and risk allele A in MHC rs9257809 with the presence of acid reflux suggests a potential pathophysiologic mechanism for the role of genetic influences in BE development.


Assuntos
Esôfago de Barrett/genética , Fatores de Transcrição Forkhead/sangue , Refluxo Gastroesofágico/genética , Antígenos HLA-C/sangue , Polimorfismo de Nucleotídeo Único , Adulto , Alelos , Estudos de Casos e Controles , Monitoramento do pH Esofágico/métodos , Feminino , Refluxo Gastroesofágico/sangue , Marcadores Genéticos , Genótipo , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Fatores de Risco
7.
Eur J Cancer ; 54: 64-68, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26735352

RESUMO

Evidence-based clinical practice guidelines are essential to ensure that childhood cancer survivors at risk of chronic health conditions receive effective long-term follow-up care. However, adult survivors of childhood cancer are not always engaged in recommended health promotion and follow-up practices, as many centres do not have a formal transition programme that prepares survivors and their families for successful transfer from child-centred to adult-oriented healthcare. The need for a specific pan-European guideline for the transition of care for childhood cancer survivors has been recognised. The first step is to define the concept of transition of care for survivors of childhood cancer based on existing evidence.


Assuntos
Assistência de Longa Duração/normas , Neoplasias/terapia , Sobreviventes , Transição para Assistência do Adulto/normas , Cuidado Transicional/normas , Adolescente , Adulto , Fatores Etários , Criança , Humanos , Assistência de Longa Duração/classificação , Guias de Prática Clínica como Assunto , Terminologia como Assunto , Fatores de Tempo , Transição para Assistência do Adulto/classificação , Cuidado Transicional/classificação , Resultado do Tratamento , Adulto Jovem
8.
Curr Oncol ; 23(6): e546-e555, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28050143

RESUMO

PURPOSE: Smoking cessation and increased physical activity (pa) have been linked to better outcomes in cancer survivors. We assessed whether socioeconomic factors influence changes in those behaviours after a cancer diagnosis. METHODS: As part of a cross-sectional study, a diverse group of cancer survivors at the Princess Margaret Cancer Centre (Toronto, ON), completed a questionnaire about past and current lifestyle behaviours and perceptions about the importance of those behaviours with respect to their health. The influence of socioeconomic indicators on smoking status and physical inactivity at 1 year before and after diagnosis were assessed using multivariable logistic regression with adjustment for clinico-demographic factors. RESULTS: Of 1222 participants, 1192 completed the smoking component. Of those respondents, 15% smoked before diagnosis, and 43% of those smokers continued to smoke after. The proportion of survivors who continued to smoke increased with lower education level (p = 0.03). Of the 1106 participants answering pa questions, 39% reported being physically inactive before diagnosis, of whom 82% remained inactive afterward. Survivors with a lower education level were most likely to remain inactive after diagnosis (p = 0.003). Lower education level, household income, and occupation were associated with the perception that pa had no effect or could worsen fatigue and quality of life (p ≤ 0.0001). CONCLUSIONS: In cancer survivors, education level was a major modifier of smoking and pa behaviours. Lower socioeconomic status was associated with incorrect perceptions about pa. Targeting at-risk survivors by education level should be evaluated as a strategy in cancer survivorship programs.

9.
Eur J Cancer Care (Engl) ; 25(3): 428-39, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26391419

RESUMO

It is rare for studies to approach psychosocial outcomes of childhood cancer in a holistic and explanatory way. Doing so would enable a greater understanding of why and in what way a young person's life may be affected by cancer. This qualitative study aimed to explore the views of childhood cancer survivors (CCS) regarding how they perceive their illness to have influenced them and their subsequent lives. Twelve CCS with a median age of 23 years old took part in either a focus group or a telephone interview. Data were analysed using thematic analysis. The main themes were altered life perspectives, perceptions of self and lasting effects on relationships. Through these themes, the survivors gave insight into how their experience had influenced their views and how this had impacted on different areas of their lives. Although positive aspects were discussed, enduring issues were reported by some. Findings suggest that despite high levels of achievement, some survivors may still benefit from further information and support especially in relation to relationships and fertility. This study will inform the development of a questionnaire aiming to collect important information on the many factors which may influence long-term psychosocial outcomes in CCS.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância/psicologia , Neoplasias/psicologia , Adaptação Psicológica , Adolescente , Adulto , Idade de Início , Atitude Frente a Saúde , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Infertilidade/psicologia , Intenção , Relações Interpessoais , Acontecimentos que Mudam a Vida , Masculino , Pesquisa Qualitativa , Autoimagem , Adulto Jovem
10.
Eur J Cancer Care (Engl) ; 25(2): 334-41, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25899560

RESUMO

In this study, we compared cancer patients preference for computerised (tablet/web-based) surveys versus paper. We also assessed whether the understanding of a cancer-related topic, pharmacogenomics is affected by the survey format, and examined differences in demographic and medical characteristics which may affect patient preference and understanding. Three hundred and four cancer patients completed a tablet-administered survey and another 153 patients completed a paper-based survey. Patients who participated in the tablet survey were questioned regarding their preference for survey format administration (paper, tablet and web-based). Understanding was assessed with a 'direct' method, by asking patients to assess their understanding of genetic testing, and with a 'composite' score. Patients preferred administration with tablet (71%) compared with web-based (12%) and paper (17%). Patients <65 years old, non-Caucasians and white-collar professionals significantly preferred the computerised format following multivariate analysis. There was no significant difference in understanding between the paper and tablet survey with direct questioning or composite score. Age (<65 years) and white-collar professionals were associated with increased understanding (both P = 0.03). There was no significant difference in understanding between the tablet and print survey in a multivariate analysis. Patients overwhelmingly preferred computerised surveys and understanding of pharmacogenomics was not affected by survey format.


Assuntos
Compreensão , Computadores de Mão , Internet , Neoplasias , Papel , Preferência do Paciente , Inquéritos e Questionários , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Computadores , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Adulto Jovem
12.
Hypertens Pregnancy ; 32(1): 60-73, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22957520

RESUMO

OBJECTIVE: To elicit women's personal understanding of future cardiovascular risk, following a pregnancy complicated by preeclampsia, and to identify the postnatal needs of these women. METHODS: Semi-structured interviews with 12 women with a recent history of preeclampsia who had attended a postnatal follow-up clinic. RESULTS: The interviews were held at a median of 47 weeks postpartum (range 24-62 weeks). Family history of cardiovascular disease was associated with a greater awareness of future cardiovascular risk. Women without traditional risk factors found it hard to envisage themselves as being at risk and may not see the relevance of such information. It may take several months after delivery for a woman to be able to fully consider her own health as well as the baby's; a reminder of risk and health information is needed. CONCLUSIONS: Although receptive to follow-up, the situational factors of being a new mother need to be taken into account to engage successfully with this patient group. Further research is needed to help clarify the extent to which a history of preeclampsia is an independent factor for future cardiovascular disease to provide a solid foundation for effective risk communication.


Assuntos
Pré-Eclâmpsia/psicologia , Adulto , Doenças Cardiovasculares , Feminino , Humanos , Cuidado Pós-Natal/psicologia , Gravidez , Medição de Risco , Adulto Jovem
13.
J Laryngol Otol ; 126(6): 638-40, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22643209

RESUMO

BACKGROUND: Imatinib therapy has been successful in gastrointestinal stromal tumours containing mutation of the KIT gene. However, there are few reported cases of successful imatinib therapy in patients with melanoma containing KIT gene mutation or c-kit protein expression. METHODS AND RESULTS: A 52-year-old man developed metastatic melanoma from a primary melanoma in the left side of the nasopharynx. The tumour was positive for c-kit protein, and there was a KIT mutation in exon 11. He was treated with imatinib. A follow-up scan one year later showed a complete response. Treatment targeting the biological characteristics of melanoma proved successful in this patient.


Assuntos
Antineoplásicos/uso terapêutico , Melanoma/tratamento farmacológico , Melanoma/secundário , Neoplasias Nasofaríngeas/patologia , Piperazinas/uso terapêutico , Proteínas Proto-Oncogênicas c-kit/genética , Pirimidinas/uso terapêutico , Antineoplásicos/administração & dosagem , Benzamidas , Éxons/genética , Expressão Gênica , Humanos , Mesilato de Imatinib , Masculino , Melanoma/genética , Pessoa de Meia-Idade , Mutação/genética , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/radioterapia , Estadiamento de Neoplasias , Piperazinas/administração & dosagem , Pirimidinas/administração & dosagem , Indução de Remissão , Resultado do Tratamento
15.
Doc Ophthalmol ; 120(2): 159-64, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19949833

RESUMO

The mfERG has proven to be a useful tool in determining central retinal and macular function. It is, however, reliant on good subject co-operation and fixation. This cannot always be guaranteed due to visual impairment or poor co-operation. Whilst a change in fixation is easy to identify with camera monitoring of the subject, a small eccentric fixation can be difficult to notice or quantify. Whilst the problem of fixation can be obviated by stimulating the retina directly with SLO (Scanning Laser Ophthalmoscope), this is expensive and a certain amount of expertize in optics is required to properly stimulate the retina. In this study, peak latency of response was investigated to see whether it changed across the retina and whether this measure could be used to help assess fixation. Eighteen normal eyes were stimulated using a 60 Hz CRT monitor with only 2 hexagons, one central and one peripheral. These hexagons were presented at three stimulation rates, fast (no filler frames between steps of the m-sequence) and slow (4 and 7 black filler frames between each step of the m-sequence), under all conditions significantly increased central hexagon latencies were noted. In a smaller experiment with 19 hexagons and only 4 subjects, it was noted a significant delay in latency was observed in ring 1 compared to ring 2 and 3 with central fixation, but not when the subjects fixed mid-peripheral and in the periphery to slow stimulation, showing that the central hexagon response was only delayed in the central hexagon when there was adequate fixation. This study suggests that latency could provide a clue to fixation particular at slow rates thereby improving the quality and confidence of recordings made clinically.


Assuntos
Eletrorretinografia/métodos , Fixação Ocular , Tempo de Reação , Humanos , Macula Lutea/fisiologia , Estimulação Luminosa/métodos , Fatores de Tempo , Visão Ocular
16.
BMJ Case Rep ; 20092009.
Artigo em Inglês | MEDLINE | ID: mdl-21686418

RESUMO

A 35-year-old man presented with keratoconus; his best corrected visual acuities were -18.00/+10.00 ×180 (6/60) oculus dexter and -10.00/+8.00 ×5 (6/36) oculus sinister. Bilateral steep central corneal thinning, paracentral ectasia and Vogts striae were present. Normal fundi. Corneal topography disclosed 7.4 dioptres of irregular astigmatism in the central 3 mm with thinning (335 µm). Electroretinography (ERG) showed no response. There were no medical or environmental influences for his keratoconus. Occurrence of keratoconus and congenital stationary night blindness (CSNB) in the patient may represent a chance association, but keratoconus has not been previously linked with CSNB1 either as a chance or true association though both show genetic predisposition.

17.
Neuroscience ; 154(1): 147-59, 2008 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-18313859

RESUMO

Stains for acetylcholinesterase (AChE) and retrograde labeling with Fluorogold (FG) were used to study olivocochlear neurons and their dendritic patterns in mice. The two methods gave similar results for location and number of somata. The total number of medial olivocochlear (MOC) neurons in the ventral nucleus of the trapezoid body (VNTB) is about 170 per side. An additional dozen large olivocochlear neurons are located in the dorsal periolivary nucleus (DPO). Dendrites of all of these neurons are long and extend in all directions from the cell bodies, a pattern that contrasts with the sharp frequency tuning of their responses. For VNTB neurons, there were greater numbers of dendrites directed medially than laterally and those directed medially were longer (on average, 25-50% longer). Dendrite extensions were most pronounced for neurons located in the rostral portion of the VNTB. When each dendrite from a single neuron was represented as a vector, and all the vectors summed, the result was also skewed toward the medial direction. DPO neurons, however, had more symmetric dendrites that projected into more dorsal parts of the trapezoid body, suggesting that this small group of olivocochlear neurons has very different physiological properties. Dendrites of both types of neurons were somewhat elongated rostrally, about 20% longer than those directed caudally. These results can be interpreted as extensions of dendrites of olivocochlear neurons toward their synaptic inputs: medially to meet crossing fibers from the cochlear nucleus that are part of the MOC reflex pathway, and rostrally to meet descending inputs from higher centers.


Assuntos
Núcleo Coclear/citologia , Dendritos/fisiologia , Neurônios/citologia , Núcleo Olivar/citologia , Animais , Vias Auditivas/fisiologia , Mapeamento Encefálico , Contagem de Células , Colina O-Acetiltransferase/metabolismo , Camundongos , Camundongos Endogâmicos CBA , Modelos Neurológicos , Neurônios/metabolismo , Estilbamidinas/metabolismo
18.
Med Biol Eng Comput ; 45(1): 69-77, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17139516

RESUMO

A system is described for the removal of eye movement and blink artefacts from single channel pattern reversal electroretinogram recordings of very poor signal-to-noise ratios. Artefacts are detected and removed by using a blind source separation technique based on the jadeR independent component analysis algorithm. The single channel data are arranged as a series of overlapping time-delayed vectors forming a dynamical embedding matrix. The structure of this matrix is constrained to the phase of the stimulation epoch: the term synchronous dynamical embedding is coined. A novel method using a marker channel with a non-independent synchronous feature is employed to identify the single most relevant source estimation for reconstruction and signal recovery. This method is non-lossy, all underlying signal being recovered. In synthetic datasets of defined noise content and in standardised real data recordings, the performance of this technique is compared to conventional fixed-threshold hard-limit rejection. The most significant relative improvements are achieved when movement and blink artefacts are greatest: no improvement is demonstrable for the random noise only situation.


Assuntos
Interpretação Estatística de Dados , Eletrorretinografia , Potenciais Evocados Visuais/fisiologia , Artefatos , Coleta de Dados , Movimentos Oculares , Sensibilidade e Especificidade
20.
Conf Proc IEEE Eng Med Biol Soc ; 2006: 4078-80, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17945824

RESUMO

Field testing of medical electrical equipment remains a topic of debate amongst biomedical engineers. A questionnaire was circulated among members of the main professional body for Medical Engineering Departments in the UK and Ireland and in the Medical Physics and Engineering Mailbase Server. The aim of the questionnaire was to establish consensus on common practice on the frequency and type of safety tests carried out in the field and common sources of hazards and risk management. Twenty-six replies were received in total. A clear majority of 54% of the respondents reported that they carried out safety tests on hospital-based medical equipment on a yearly basis. For other equipment, regular tests were carried out by 58% on loan equipment and by 69% on medical electrical systems. Laboratory equipment on the other hand were not tested in 42% of the cases. Domiciliary and research equipment were only tested in 11% and 15% of the cases respectively. A clear majority of 93% said that they label equipment after tests, 34% said that they always record the actual values (as opposed to pass or fail) and 54% said they carry out functional test as part of the safety test. Although 61% of failures were attributed to the mains lead, only 50% of the respondents said that they had a management system in place for detachable mains leads.


Assuntos
Engenharia Biomédica/tendências , Eletrônica Médica , Técnicas de Laboratório Clínico , Eletrônica Médica/normas , Segurança de Equipamentos , Equipamentos e Provisões Hospitalares , Reino Unido
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...