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1.
BMC Neurol ; 15: 215, 2015 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-26492863

RESUMO

BACKGROUND: The visual vertical (VV) consists of repeated adjustments of a luminous rod to the earth vertical. How many trials are required to reach consistency in this measure? This question has never been addressed despite the widespread clinical use of the measurement in stroke rehabilitation. METHODS: VV perception was assessed (10 trials) in 117 patients undergoing rehabilitation after a first hemisphere stroke. The intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were calculated for each patient category: with contralesional VV bias (n = 48), ipsilesional VV bias (n = 17) and normal VV (n = 52). RESULTS: For patients with VV biases, 6 trials were required to reach high inter-trial reliability (contralesional: ICC = 0.9, SEM = 1.36°; ipsilesional: ICC = 0.896, SEM = 0.96°). For patients with normal VV, a minimum of 10 trials was required (ICC = .728, SEM = 1.13°). A set of 6 trials correctly classified 96 % of patients. CONCLUSIONS: In the literature, 10 is the most frequently used number of trials used to assess VV orientation. Our study shows that 10 trials are required to adequately measure VV orientation in non-selected subacute stroke patients. For complex protocols imposing a decrease in the number of trials in each condition, 6 trials are needed to identify VV biases in most patients.


Assuntos
Testes Neuropsicológicos/normas , Transtornos da Percepção/diagnóstico , Percepção Espacial/fisiologia , Acidente Vascular Cerebral/diagnóstico , Percepção Visual/fisiologia , Idoso , Viés , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Percepção/etiologia , Equilíbrio Postural , Reprodutibilidade dos Testes , Acidente Vascular Cerebral/complicações , Reabilitação do Acidente Vascular Cerebral
2.
Spinal Cord ; 53(5): 387-94, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25510189

RESUMO

OBJECTIVES: To study the postural adaptations of subjects with incomplete spinal cord injury (iSCI) and non-injured subjects during overground walking on level and inclined surfaces. METHODS: Six subjects with iSCI and seven non-injured subjects walked on an inclined surface (slope: 15%) and a level surface at their natural gait speed and at a slow gait speed (non-injured subjects only). Maximal stabilizing and minimal destabilizing forces were calculated to quantify dynamic balance during walking. Correlational analysis identified the variables that influence these stabilizing and destabilizing forces. RESULTS: Subjects with iSCI and good sensorimotor recovery were similar to non-injured subjects with respect to maximal stabilizing and minimal destabilizing forces when they walked at the same speed. The MaxSF was mainly explained by the center of pressure speed and step length, whereas the minimal destabilizing force was moderately correlated with body mass and height. CONCLUSION: The influence of gait speed on balance should be considered with a group comparison. With regard to dynamic balance, highly functioning subjects with iSCI do not seem to be sufficiently challenged while walking at their preferred gait speed. Asking individuals with subtle impairments to walk faster following an iSCI may reveal postural adaptations and have an effect on balance abilities.


Assuntos
Adaptação Fisiológica/fisiologia , Equilíbrio Postural/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Caminhada/fisiologia , Idoso , Fenômenos Biomecânicos , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Postura/fisiologia , Traumatismos da Medula Espinal/reabilitação , Estatística como Assunto
3.
B-ENT ; 10(4): 303-7, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25654955

RESUMO

BACKGROUND: Carcinoid tumours are rare, particularly in the head and neck region. When occurring in this area, they mainly affect the larynx. The first case of primary well-differentiated carcinoid tumour arising from the nasopharynx was documented in 2009 and treated by combined external beam radiation and cold somatostatin analogue with a fatal outcome. To our knowledge, no case of this type of lesion has been successfully treated with surgery and radiotherapy until now. OBJECTIVE: To make physicians aware that typical carcinoid nasopharyngeal tumour can be treated by surgery and adjuvant radiotherapy. METHOD: We report the management of a typical carcinoid nasopharyngeal tumour in a 68-year-old female successfully treated with endoscopic surgery and adjuvant radiotherapy. We also review the relevant literature. CONCLUSION: Patients with close margins at the time of the surgery may need adjuvant radiotherapy to prevent recurrence. After a negative octreotide scintigraphy, periodical follow-up only is sufficient.


Assuntos
Tumor Carcinoide/terapia , Endoscopia/métodos , Neoplasias Nasofaríngeas/terapia , Idoso , Tumor Carcinoide/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Neoplasias Nasofaríngeas/patologia , Radioterapia Adjuvante
4.
Percept Mot Skills ; 130(6): 2327-2342, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37654231

RESUMO

Mechanical vibration of the Achilles tendon is widely used to analyze the role of proprioception in postural control. The response to this tendon vibration (TV) has been analyzed in the upright posture, but the feet positions have varied in past research. Moreover, investigators have addressed only temporal parameters of the center of pressure (CoP). We investigated the effect of TV on both temporal and spectral characteristics of the CoP motion. Eighteen healthy young adults, stood barefoot, with one foot on each side of a dual platform, wearing glasses with opaque lenses. We applied 20 seconds of Achilles TV (bilaterally with inertial vibrators at a frequency of 80 Hz and an amplitude of .2-.5 mm). We analyzed CoP signals pre-vibration (PRE,4-seconds), during vibration (VIB,20 seconds), and after vibration cessation (REC,20 seconds). We repeated this protocol in natural and standardized positions (15° feet angular opening). For determining CoP amplitude and velocity, we divided the 20 seconds into five phases of four seconds each and calculated spectral parameters for the whole 20-second signals. There was an adaptation process in the speed of the CoP mediolateral (p < .01) and anteroposterior (p < .01) and in the displacement of the CoP anteroposterior (p < .01), with higher values in the VIB condition. Velocity and displacement decreased progressively in the REC condition. Median and peak frequencies were higher in the VIB condition when compared to the REC condition, but only in the mediolateral direction (p = .01). The standardized foot position led to increased speed in CoP mediolateral, anteroposterior, and mediolateral displacement (p < .01). CoP spectral characteristics were not affected by foot positioning. We concluded that adaptation of CoP motion in the presence of TV and after its cessation are observable both in time and frequency domains. Feet positioning influenced CoP motion in the presence of TV and after its cessation but it did not affect its spectral characteristics.


Assuntos
Tendão do Calcâneo , Adulto Jovem , Humanos , Tendão do Calcâneo/fisiologia , Vibração , Propriocepção/fisiologia , Equilíbrio Postural/fisiologia , Posição Ortostática
5.
Arch Gerontol Geriatr ; 99: 104606, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34896795

RESUMO

PURPOSE: . The concept of lockdown in relation to COVID-19 is thought to have an indirect impact on the quality of life and well-being of the elderly due to its consequences on the physical, psychological, and cognitive health of individuals. However, previous published studies on this subject are limited in terms of methodological approach used, including the absence of pre-confinement status and the type of experimental design, which is often cross-sectional. The present study proposes a longitudinal design with pre-confinement measures. It assesses changes in quality of life, perceived health, and well-being by comparing the period before lockdown (T1 = December 2019), three months after the start of the first lockdown (T2 = June 2020), and during the second lockdown (T3 = January 2021) due to COVID-19. MATERIALS AND METHODS: . This study is conducted with a group of 72 healthy elderly persons. They completed an electronic (online) survey assessing personal factors, activities, and participation as well as responding to the EuroQol-5D and Warwick-Edinburgh Mental Well-being Scale. RESULTS: . A decrease in quality of life, perceived health and well-being was observed between T1 and T2 and between T1 and T3, but no difference was reported between the two lockdown periods. The variables associated with these changes included energy level, level of happiness, physical activity, change in medical condition, memory difficulties, level of perceived isolation and age. CONCLUSION: . This study will help to target variables that may have a deleterious effect on older adults for consideration in future confinement settings and for preventive purposes.


Assuntos
COVID-19 , Qualidade de Vida , Idoso , Controle de Doenças Transmissíveis , Estudos Transversais , Humanos , SARS-CoV-2
6.
Work ; 68(3): 789-796, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33612521

RESUMO

BACKGROUND: Airplane de-icing technicians work from either an open-basket or closed-basket. OBJECTIVE: The objective of this study is to identify the tasks that have an influence on the physical fatigue of open-basket aircraft de-icing technicians. METHODS: In a Canadian airport during the winter of 2016-2017, a field study was conducted in which the heart rate of 12 volunteer participants was collected. The data was analyzed along with the 22 tasks that make up the activity of open-basket aircraft de-icing. For each participant, the mean absolute cardiac cost per task was compared. The evolution of the cardiac signal based on the resting heart rate and steady state limit was also characterized. RESULTS: According to the cumulative results fatigue occurs for periodic tasks as well as double tasks. More precisely, the most physically fatiguing tasks are spraying de-icing and anti-icing fluids, moving the basket and truck, as well as tactile control and de-icing quality control at ground level. CONCLUSIONS: Similar studies would need to be conducted in other aircraft de-icing facilities to improve the generalization of the results.


Assuntos
Aeronaves , Fadiga , Canadá , Humanos , Estações do Ano
7.
Spinal Cord ; 48(3): 245-50, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19773797

RESUMO

STUDY DESIGNS: Longitudinal and correlational study with repeated measures. OBJECTIVES: The aim of this study was to test the concurrent validity of the Berg Balance Scale (BBS) for a spinal cord injury (SCI) population. PARTICIPANTS: A total of 32 individuals with an ASIA D SCI walking 10 m independently, with or without walking assistive devices. SETTING: An intensive rehabilitation center in Montréal, Canada. METHODS: Subjects were evaluated on the BBS, the Walking Index for Spinal Cord Injury (WISCI II), the Spinal Cord Injury Functional Ambulation Inventory (SCI-FAI), the 10-m walk test (10MWT) and the Timed Up and Go (TUG). Individuals were reassessed during rehabilitation when progressing to a device providing less support or to unassisted gait. RESULTS: All walking tests were highly correlated with the BBS (0.714

Assuntos
Paraplegia/fisiopatologia , Equilíbrio Postural/fisiologia , Quadriplegia/fisiopatologia , Adulto , Idoso , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Limitação da Mobilidade , Reprodutibilidade dos Testes , Tecnologia Assistiva , Caminhada/fisiologia , Adulto Jovem
8.
Rev Laryngol Otol Rhinol (Bord) ; 131(4-5): 269-74, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21866738

RESUMO

OBJECTIVE: The extent of the surgery required when sinonasal inverted papilloma (IP) originates in the maxillary sinus is still the subject of debate. The principal aim of the study was to evaluate the efficacy of exclusive endoscopic removal or when combined with a limited vestibular anterior antrostomy of the maxillary IP. METHODS: A retrospective analysis was carried out of 64 patients with IP treated in our university tertiary referral center from 1993-2007. Endoscopic removal of the IP was done for all patients, either exclusively or combined with an open approach. All patients were followed up for more than 1 year and the local control rate has been compared between patients with maxillary IP and others, and with both approaches. RESULTS: The overall recurrence rate was 14% (9/64), for a mean follow up of 48 months (12-120 months). Twenty-three patients (23/64) had maxillary IP. Ten of them had endoscopic resection alone, 13 had a combined approach (1 with lateral rhinotomy). There were 4 recurrences (17%) three of which had had endoscopic surgery alone. We did not perform a medial maxillectomy in the first instance. There were no cases of epiphora or atrophic rhinitis. conclusion: We showed that the combined method (endoscopic assisted by a minimal vestibular approach) was an efficient and safe method to treat maxillary sinus IP. This approach could preserve the lacrimal duct and the inferior turbinate when these structures were not involved, even when there was a large maxillary sinus extension of the disease.


Assuntos
Neoplasias do Seio Maxilar/cirurgia , Papiloma Invertido/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Endoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Otorrinolaringológicos , Estudos Retrospectivos
9.
J Biomech ; 42(3): 379-82, 2009 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-19131066

RESUMO

Postural stability is essential to functional activities. This paper presents a new model of dynamic stability which takes into account both the equilibrium associated with the body position over the base of support (destabilizing force) and the effort the subject needs to produce to keep his/her centre of mass inside the base of support (stabilizing force). The ratio between these two forces (destabilizing over stabilizing) is calculated to provide an overall index of stability for an individual. Preliminary results from data collected during walking at preferred and maximal safe speed in four older adults (aged from 64 to 84yr) showed that both forces are lower for subjects with reduced maximal gait speed. In addition, the stabilizing force increases by 2-3 times from preferred to maximal speed, while the destabilizing force barely changes with gait speed. Overall, the model through the index of stability attributes lower dynamic stability to subjects with lower maximal gait speed. These preliminary results call for larger-scale studies to pursue the development and validation of the model and its application to different functional tasks.


Assuntos
Postura/fisiologia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Humanos , Equilíbrio Postural/fisiologia , Caminhada/fisiologia
10.
Rev Laryngol Otol Rhinol (Bord) ; 130(4-5): 255-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20597407

RESUMO

OBJECTIVE: To evaluate the outcome and morbidity of endoscopic resection of sinonasal adenocarcinomas. METHODS: This is a case series of 17 patients diagnosed with sinonasal adenocarcinoma that were resected endoscopically between 1999 and 2008. RESULTS: The surgery constituted the first line of treatment for all patients. Five anterior skull base reconstructions were done. Post-operative meningoencephalitis and minimal epistaxis were the complications reported. The mean follow-up was 3 years [6-107 months]. To date, there have been two local recurrences at 6 months of an insufficient resection of a tumour classified pT4 and 25 months of a pT2 resected with safe margins. Another patient presented an unique metastasis in the parietal lobe 42 months after the resection of tumour pT4 extended to the frontal lobe. Two deaths unrelated to the disease were reported while thirteen patients remained free of disease (76.5%). CONCLUSION: The endoscopic approach is a safe and effective treatment in selected cases of sinonasal adenocarcinomas. This procedure is less invasive than conventional surgery but requires an optimal preoperative imaging protocol and an experienced surgical team. These encouraging results have to be confirmed by a larger cohort and a longer follow-up.


Assuntos
Adenocarcinoma/cirurgia , Endoscopia , Neoplasias dos Seios Paranasais/cirurgia , Adenocarcinoma/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Neoplasias dos Seios Paranasais/mortalidade , Complicações Pós-Operatórias
11.
Med Biol Eng Comput ; 46(3): 299-306, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18193467

RESUMO

This paper describes the design, technical characteristics and first results of an adjustable instrumented chair with a sitting surface that records the forces under each thigh. The seat includes a force platform assembly suitable for measuring the magnitude, position and direction of the force applied to each thigh while sitting or rising from the chair. The natural frequency of the chair fixed to the floor was found to be 14.0 +/- 2 Hz with an estimated damping of xi = 0.20. Static tests showed that the maximal errors were 2% of the full-scale output (726 N vertically, 164 N horizontally) for both vertical and horizontal forces. The root mean square error of the center of pressure location was estimated as 5 mm. Preliminary data on the net joint moment at the hips of one healthy subject computed with and without consideration for the forces under the thighs revealed significant amplitude differences. In conclusion, the results indicate that the characteristics of the instrumented chair are acceptable and the chair can be used to assess the biomechanics of sitting and sit-to-stand and stand-to-sit tasks in various subject populations.


Assuntos
Fenômenos Biomecânicos/instrumentação , Movimento/fisiologia , Postura/fisiologia , Coxa da Perna/fisiologia , Desenho de Equipamento , Humanos , Masculino
12.
Electromyogr Clin Neurophysiol ; 48(3-4): 147-62, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18551835

RESUMO

The purpose of this study was to compare the electromyographic (EMG) fatigue indices computed from short-time Fourier transform (STFT) and wavelet transform (WAV), by analyzing their criterion validity and test-retest reliability. The effect of averaging spectral estimates within and between repeated contractions (cycles) on EMG fatigue indices was also demonstrated. Thirty-one healthy subjects performed trunk flexion-extension cycles until exhaustion on a Biodex dynamometer. The load was determined theoretically as twice the L5-S1 moment produced by the trunk mass. To assess reliability, 10 subjects performed the same experimental protocol after a two-week interval. EMG signals were recorded bilaterally with 12 pairs of electrodes placed on the back muscles (at L4, L3, L1 and T10 levels), as well as on the gluteus maximus and biceps femoris. The endurance time and perceived muscle fatigue (Borg CR-10 scale) were used as fatigue criteria. EMG signals were processed using STFT and WAV to extract global (e.g, median frequency and instantaneous median frequency, respectively) or local (e.g., intensity contained in 8 frequency bands) information from the power spectrum. The slope values of these variables over time, obtained from regression analyses, were retained as EMG fatigue indices. EMG fatigue indices (STFT vs. WAV) were not significantly different within each muscle, had a variable association (Pearson's r range.: 0.06 to 0.68) with our fatigue criteria, and showed comparable reliability (Intra-class correlation range: 0.00 to 0.88), although they varied between muscles. The effect of averaging, within and between cycles, contributed to the strong association between EMG fatigue indices computed from STFT and WAV. As for EMG spectral indices of muscle fatigue, the conclusion is that both transforms carry essentially the same information.


Assuntos
Eletromiografia/métodos , Contração Isométrica/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Processamento de Sinais Assistido por Computador , Adulto , Feminino , Análise de Fourier , Humanos , Região Lombossacral , Masculino , Dinamômetro de Força Muscular , Resistência Física/fisiologia , Valores de Referência , Suporte de Carga/fisiologia
13.
J Clin Invest ; 95(2): 593-602, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7860743

RESUMO

The aim of this study was to determine whether a selective increase in the level of insulin in the blood perfusing the brain is a determinant of the counterregulatory response to hypoglycemia. Experiments were carried out on 15 conscious 18-h-fasted dogs. Insulin was infused (2 mU/kg per min) in separate, randomized studies into a peripheral vein (n = 7) or both carotid and vertebral arteries (n = 8). This resulted in equivalent systemic insulinemia (84 +/- 6 vs. 86 +/- 6 microU/ml) but differing insulin levels in the head (84 +/- 6 vs. 195 +/- 5 microU/ml, respectively). Glucose was infused during peripheral insulin infusion to maintain the glucose level (56 +/- 2 mg/dl) at a value similar to that seen during head insulin infusion (58 +/- 2 mg/dl). Despite equivalent peripheral insulin levels and similar hypoglycemia; steady state plasma epinephrine (792 +/- 198 vs. 2394 +/- 312 pg/ml), norepinephrine (404 +/- 33 vs. 778 +/- 93 pg/ml), cortisol (6.8 +/- 1.8 vs. 9.8 +/- 1.6 micrograms/dl) and pancreatic polypeptide (722 +/- 273 vs. 1061 +/- 255 pg/ml) levels were all increased to a greater extent during head insulin infusion (P < 0.05). Hepatic glucose production, measured with [3-3H]glucose, rose from 2.6 +/- 0.2 to 4.3 +/- 0.4 mg/kg per min (P < 0.01) in response to head insulin infusion but remained unchanged (2.6 +/- 0.5 mg/kg per min) during peripheral insulin infusion. Similarly, gluconeogenesis, lipolysis, and ketogenesis were increased twofold (P < 0.001) during head compared with peripheral insulin infusion. Cardiovascular parameters were also significantly higher (P < 0.05) during head compared with peripheral insulin infusion. We conclude that during hypoglycemia in the conscious dog (a) the brain is directly responsive to physiologic elevations of insulin and (b) the response includes a profound stimulation of the autonomic nervous system with accompanying metabolic and cardiovascular changes.


Assuntos
Encéfalo/metabolismo , Insulina/sangue , Insulina/farmacologia , Ácido 3-Hidroxibutírico , Acetoacetatos/metabolismo , Alanina/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Circulação Cerebrovascular , Estado de Consciência , Cães , Epinefrina/sangue , Ácidos Graxos não Esterificados/metabolismo , Feminino , Glucose/metabolismo , Glicerol/metabolismo , Glicólise/efeitos dos fármacos , Hidroxibutiratos/metabolismo , Hipoglicemia/metabolismo , Infusões Intra-Arteriais , Insulina/administração & dosagem , Lactatos/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Norepinefrina/sangue
14.
J Perinatol ; 27(4): 203-8, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17304208

RESUMO

BACKGROUND: The Neonatal Intensive Care Unit (NICU) can be ethically charged, which can create challenges for health-care workers. OBJECTIVE: To determine the frequency with which nurses and residents have experienced ethical confrontations and what factors are associated with increased frequency. DESIGN/METHODS: An anonymous questionnaire was distributed to nurses in a university center, a high-risk obstetric service, a maternity hospital NICU with 85% in-born patients and an outborn NICU, most of whose preterm admissions are those with surgical complications. Obstetric and pediatric residents in the four universities of the province also received the questionnaire, which included demographics, opinions regarding the gestational age threshold at which resuscitation of a premature infant with bradycardia was appropriate, knowledge of cerebral palsy (CP) outcomes (as an indicator of knowledge about long-term sequelae of prematurity) and questions about ethical confrontation in the NICU. RESULTS: Two hundred and seventy-nine caregivers participated (115 full time nurses and 164 residents). All the distributed questionnaires were completed. Frequent ethical confrontation was reported by 35% of the nurses and 19% of the residents. Among the nurses, moral distress differed significantly between work environments. Nurses working in an out-born NICU and obstetric nurses were more likely to overestimate CP prevalence (P<0.05). Nurses who overestimated CP rates had higher thresholds for resuscitation and were more likely to experience ethical confrontations. Of the residents, 60% were pediatric and 40% obstetric. All groups of residents frequently overestimated the prevalence of CP, and knowledge differed significantly by residency program (P<0.05). The residents who overestimated CP rates had higher thresholds for resuscitation, had more incorrect answers regarding prematurity outcomes and were less likely to have ethical confrontations. CONCLUSIONS: A large proportion of nurses and residents report frequent ethical confrontations. Many residents and nurses have limited knowledge of outcomes and high threshold for resuscitation. Ethical confrontation is more common among nurses with poor knowledge about outcomes, and less common in residents with poor knowledge about outcomes.


Assuntos
Paralisia Cerebral/diagnóstico , Ética Clínica , Terapia Intensiva Neonatal/ética , Internato e Residência/ética , Enfermagem Neonatal/ética , Ressuscitação/ética , Adulto , Bradicardia/terapia , Paralisia Cerebral/enfermagem , Paralisia Cerebral/terapia , Idade Gestacional , Hospitais Universitários , Humanos , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Recém-Nascido , Recém-Nascido Prematuro , Terapia Intensiva Neonatal/psicologia , Terapia Intensiva Neonatal/normas , Modelos Logísticos , Ressuscitação/enfermagem , Inquéritos e Questionários
15.
J Neurosci ; 20(9): 3456-68, 2000 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10777809

RESUMO

Systemic injection of the endotoxin lipopolysaccharide (LPS) upregulates the gene encoding CD14 early in the circumventricular organs (CVOs) and later in the brain parenchyma. The present study tested the hypothesis that the parenchymal production of the proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) by microglial cells is responsible for triggering CD14 transcription in an autocrine/paracrine loop-like manner. In a first set of experiments, Sprague Dawley rats were killed 1, 3, 6, and 12 hr after an intracerebroventricular administration of recombinant rat TNF-alpha or vehicle solution. Second, anti-rat TNF-alpha-neutralizing antibody or vehicle solution was administrated into the lateral ventricle 10 hr before an intraperitoneal injection of LPS. Central administration of the cytokine caused a strong induction of IkappaBalpha, TNF-alpha, and CD14 mRNA in parenchymal microglial cells. The hybridization signal for these transcripts was localized to the edge of the ventricles and the site of infusion. The time-related expression of each mRNA suggested that TNF-alpha has the ability to trigger its own production followed by the transcription of the LPS receptor; the signal for IkappaBalpha, TNF-alpha, and CD14 peaked at 1, 3, and 6 hr, respectively. The genes encoding TNF-alpha and mCD14 were also induced in the CVOs and within microglial cells across the brain parenchyma in response to intraperitoneal LPS administration. This induction in parenchymal cells of the brain was prevented in animals that received the anti-TNF-antisera intracerebroventricularly 10 hr before the systemic treatment with the endotoxin. The present data provide the evidence that microglial-derived TNF-alpha is responsible for the production of the LPS receptor CD14 during endotoxemia. This autocrine/paracrine stimulatory loop may be of great importance in controlling the inflammatory events that take place in the CNS during innate immune response as well as under pathological conditions.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Endotoxemia/metabolismo , Proteínas I-kappa B , Receptores de Lipopolissacarídeos/metabolismo , Microglia/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Proteínas de Ligação a DNA/efeitos dos fármacos , Endotoxemia/induzido quimicamente , Receptores de Lipopolissacarídeos/efeitos dos fármacos , Lipopolissacarídeos , Masculino , Microglia/efeitos dos fármacos , Inibidor de NF-kappaB alfa , NF-kappa B , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia
16.
J Electromyogr Kinesiol ; 15(4): 393-405, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15811610

RESUMO

The plantarflexor, hip extensor and hip flexor muscle groups contribute by their concentric action to generate most of the energy during level gait in healthy subjects. The goal of the present study was to determine, during the main energy generation phases, the relative demand of these three groups in 14 healthy subjects walking at four cadences (self-selected, 60, 80 and 120 steps/min). The muscular utilization ratio (MUR), that compares the net joint moment obtained during gait to the maximal potential moment (MPM) at each percentage of the gait cycle, was used to estimate the mechanical relative demand. The MPM values were obtained by regression equations developed from torque data measured with a Biodex dynamometric system. The results showed that the peak MURs increased with gait cadence. The peak values were not significantly different between sides for all cadences despite mean absolute lateral differences ranging from 7% to 10%. The mean peak MURs of both sides ranged from 51.3% to 62.6%, from 20.7% to 49.9% and from 14.9% to 42.5%, for the plantarflexors, hip flexors and hip extensors, respectively. Highly significant associations were found between the MURs and net moments (numerator of the MUR ratio), with Pearson coefficients (r) superior to 0.80 for all muscles groups. The association between the MURs and the maximal potential moments (denominator of MUR ratio) was lower (0.01

Assuntos
Articulação do Tornozelo/fisiologia , Eletromiografia/métodos , Articulação do Quadril/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Esforço Físico/fisiologia , Análise e Desempenho de Tarefas , Caminhada/fisiologia , Adulto , Diagnóstico por Computador/métodos , Feminino , Humanos , Masculino , Torque
17.
Med Biol Eng Comput ; 43(5): 552-6, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16411626

RESUMO

The paper describes the design, technical characteristics and first results of an adjustable staircase with commercial force plates embedded in the steps and custom force transducers as part of the handrail supports. For the railing assembly, the greatest errors (< 10% of maximum signal) and cross-talk range (0.58-6.74%) were in the medial-lateral direction and were corrected using a calibration matrix. Power spectral density analyses showed free vibration frequency responses for both the railing (15 Hz) and steps (38.6 Hz) that were relatively distinct from lower applied forces recorded during stair ascent. The creation of standardised filtering protocols was therefore possible to provide step reaction force signals identical to the literature and examples of upper-limb reaction forces that have not been shown before. Such a staircase will allow a more complete study of full body contributions to stair walking across various subject populations.


Assuntos
Marcha/fisiologia , Extremidade Inferior/fisiologia , Extremidade Superior/fisiologia , Fenômenos Biomecânicos/instrumentação , Desenho de Equipamento , Humanos , Locomoção/fisiologia , Transdutores
18.
J Neuropathol Exp Neurol ; 58(1): 61-77, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10068315

RESUMO

Tumor necrosis factor (TNF)-alpha is usually referred to as a proinflammatory cytokine that plays a central role in initiating the cascade of other cytokines and factors for an appropriate immune response to infection. Like systemic phagocytes, recent studies have reported that specific cellular populations of the CNS have the ability to express and release the proinflammatory cytokine in response to peripheral administration of the bacterial endotoxin lipopolysaccharide (LPS). Whether such phenomenon represents a general mechanism of systemic immunogenic stimuli and how the severity of the challenge may influence TNF-alpha transcription in the brain has yet to be defined. Adult male rats were sacrificed 1, 3, 6, 12, 24 and 48 hours (h) after intraperitoneal (IP) injection of LPS (25-250 microg/100 g) or intramuscular (IM) injection of turpentine. Brains and pituitary glands were removed, cut, and TNF-alpha mRNA assayed by in situ hybridization using a full-length rat cRNA probe. The results show no positive signal under basal conditions or following sterile inflammation into the left hind limb. Systemic LPS caused a profound increase in the expression of the gene encoding TNF-alpha in the leptomeninges, choroid plexus (chp) and all sensorial circumventricular organs (CVOs). Interestingly, a migratory-like pattern of TNF-alpha-positive cells became apparent around the sensorial CVOs at 3 h, while a ubiquitous-like positive signal was found throughout the brain 6 h after the injection with the highest dose of LPS. The IP LPS injection also stimulated TNF-alpha transcription in the anterior pituitary lobe; the signal was maximal 1 h after the injection and returned gradually to basal levels at 12 h, whereas the mRNA encoding the cytokine was detected later in the neurohypophysis, i.e. 3 and 6 h post challenge. Dual-labeling procedure provided the evidence of an LPS-dependent induction of TNF-alpha in different phagocytic cellular populations of the brain, including parenchymal microglial cells during severe endotoxemia. The fact that these myeloid-derived cells have the ability to express the LPS receptor CD14 in the brain may well explain the transcriptional activation of the cytokine in response to the bacterial endotoxin, but not to systemic localized inflammation.


Assuntos
Encéfalo/metabolismo , Regulação da Expressão Gênica/fisiologia , Hipófise/metabolismo , Fator de Necrose Tumoral alfa/genética , Animais , Formação de Anticorpos , Relação Dose-Resposta a Droga , Código Genético , Inflamação/metabolismo , Injeções Intramusculares , Lipopolissacarídeos/farmacologia , Masculino , Modelos Biológicos , Ratos , Ratos Sprague-Dawley , Terebintina/farmacologia
19.
Biol Psychiatry ; 45(11): 1440-6, 1999 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10356626

RESUMO

BACKGROUND: The pathophysiology of depression may include synaptic hypoactivity of left prefrontal cortex. Several groups of investigators have described improved mood associated with rapid transcranial magnetic stimulation (rTMS) but have not looked for possible cognitive side effects associated with left prefrontal magnetic stimulation. METHODS: We measured the effects of left prefrontal rTMS on mood, cognition, and motor evoked potential threshold in 10 patients with medication-resistant major depression. RESULTS: In a 2-week open trial of left prefrontal rTMS off antidepressant medications, scores on the Hamilton Rating Scale for Depression and the Beck Depression Inventory decreased by 41% and 40%, respectively. After resuming pre-rTMS antidepressant medication, improvement in mood was still significant at 1 and 3 months later. rTMS had no adverse effects on neuropsychological performance. rTMS treatments were associated with significant decreases in motor evoked potential threshold in the 9 of 10 patients who remained off psychotropic medications during the 2-week treatment period. CONCLUSIONS: These preliminary data suggest that left prefrontal rTMS is safe and improves mood in patients with medication-resistant major depression. Changes in motor evoked potential threshold suggest that prefrontal rTMS may alter brain activity at sites remote from the stimulation. Double-blind, sham-controlled studies are needed.


Assuntos
Cognição/efeitos da radiação , Transtorno Depressivo/terapia , Campos Eletromagnéticos , Potencial Evocado Motor/efeitos da radiação , Córtex Pré-Frontal/efeitos da radiação , Adulto , Idoso , Transtorno Depressivo/fisiopatologia , Limiar Diferencial/efeitos da radiação , Campos Eletromagnéticos/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/fisiologia , Testes Neuropsicológicos , Estimulação Física , Estatísticas não Paramétricas , Resultado do Tratamento
20.
Arch Neurol ; 58(10): 1682-4, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11594930

RESUMO

BACKGROUND: The pathogenesis of ballism is uncertain and may involve more than one mechanism; treatment is not always efficacious. OBJECTIVE: To provide evidence of a nondopaminergic mechanism and the potential for a prompt and nearly complete response to a serotonergic agent. METHODS: Report of 2 separate trials of sertraline hydrochloride in a single patient. RESULTS: Complete remission of symptoms within 48 hours of each drug trial. CONCLUSION: Sertraline may offer an alternative with a better adverse effect profile than dopamine receptor blockers in the treatment of patients with ballism.


Assuntos
Antidepressivos/uso terapêutico , Discinesias/tratamento farmacológico , Inibidores Seletivos de Recaptação de Serotonina/uso terapêutico , Sertralina/uso terapêutico , Idoso , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Hemorragia Cerebral/diagnóstico , Infarto Cerebral/diagnóstico , Eletrocardiografia , Humanos , Imageamento por Ressonância Magnética , Masculino , Resultado do Tratamento
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