RESUMO
Background: Advanced gynaecological procedures often include extensive pelvic dissections, with the nervous structures involved in the disease. Nerve-sparing and preservation is a key factor in reducing postoperative morbidity. Objectives: The goal of this review is to describe in detail the structure of the pelvic nerves and to gather information from other surgical specialties to give recommendations for safe nerve dissection applied in different gynaecological subspecialties. Materials and Methods: An extensive literature review was carried out in PubMed and Google Scholar. The search included articles concerning peripheral nerve anatomy, mechanisms of injury and different dissection techniques, with the most exhaustive being analysed for the review. Articles from different fields of medicine like orthopaedics, plastic surgery, maxillofacial surgery dealing with peripheral nerve injuries and repair have been reviewed. Results: The following review demonstrates the in-depth anatomy and mechanism of injury of the peripheral nerves, describes the different techniques for neurolysis and proposes some directions for safe nerve dissection. Conclusion: When performing complex gynaecological surgeries, the surgeon should avoid unnecessary nerve handling, apply nerve-sparing techniques whenever possible and use the new devices to preserve the nervous structures. Advanced gynaecological surgeries should be performed in specialised centres by expert surgeons with comprehensive knowledge in neuropelveology. What is new?: To our knowledge, this is the first article focused on peripheral nerves that collects data from such a wide range of specialties in order to propose the most comprehensive recommendations that could be applied in pelvic surgery.
RESUMO
Fatigue is one of the most common symptoms of rheumatoid arthritis (RA). There is strong evidence that physical activity is an effective way to reduce fatigue. OBJECTIVE: To evaluate the effectiveness of aerobic exercise (walking) to reduce fatigue in RA patients in the health resort setting. MATERIAL AND METHODS: The study involved 102 female patients with RA (age 54.38±11.3 years, body mass index 20-29 kg/m2, DAS28-ESR ≤3.2, with severe fatigue of VAS ≥50) who received 21 days of health resort treatment. The health-improving and therapeutic complex includes dosed physical activity, aerobic exercises (walking). Visual analog scale (VAS0-100) and Bristol Rheumatoid Arthritis Fatigue Scale-Numerical Rating Scale (BRAF-NRS V2) were used to assess fatigue, and the 50-meter walking test was used to evaluate the functional status of patients. RESULTS: A correlation between walking duration and the number of steps at a distance of 50 m (p<0.001) as well as between these indices and fatigue (p<0.001) was shown. A positive effect of a standard three-week medical rehabilitation program for patients with RA on fatigue NRS severity (p=0.003) and NRS effect (p=0.037), as well as on patients' functional status (reduced time spent on the 50-meter test, p=0.01) was demonstrated. When comparing groups of RA patients with low (group 1, <5000-6000 steps per day) and optimal (group 2, ≥7000-8000 steps per day) aerobic exercise, positive results were noted in the short term (at 3 weeks) (p<0.001). CONCLUSION: Aerobic exercise is a promising intervention for treating fatigue in rheumatoid arthritis patients. Medical rehabilitation in a resort setting is the best starting point to encourage performing regular physical activity, as well as the best way to develop exercise programs tailored to rheumatoid arthritis patients.
Assuntos
Artrite Reumatoide , Estâncias para Tratamento de Saúde , Adulto , Idoso , Artrite Reumatoide/complicações , Artrite Reumatoide/terapia , Exercício Físico , Terapia por Exercício , Fadiga/diagnóstico , Fadiga/etiologia , Fadiga/terapia , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
The pelvic organ prolapse (POP) is a common gynaecological problem, affecting nearly 50% of women over 40. The sacrocolpopexy using a synthetic mesh is now considered the "gold standard" for management of women with apical prolapse. In April 2019 the FDA placed a ban on the production of transvaginal meshes for prolapse due to late complications. The meshes for abdominal repair of POP are still used, but in future they may also be prohibited. The goal of the following video is to present a mesh-less modification of two techniques used for apical organ prolapse, the sacrocolpopexy and the pectopexy.
RESUMO
Fatty acid photodecarboxylase (FAP) is a photoenzyme with potential green chemistry applications. By combining static, time-resolved, and cryotrapping spectroscopy and crystallography as well as computation, we characterized Chlorella variabilis FAP reaction intermediates on time scales from subpicoseconds to milliseconds. High-resolution crystal structures from synchrotron and free electron laser x-ray sources highlighted an unusual bent shape of the oxidized flavin chromophore. We demonstrate that decarboxylation occurs directly upon reduction of the excited flavin by the fatty acid substrate. Along with flavin reoxidation by the alkyl radical intermediate, a major fraction of the cleaved carbon dioxide unexpectedly transformed in 100 nanoseconds, most likely into bicarbonate. This reaction is orders of magnitude faster than in solution. Two strictly conserved residues, R451 and C432, are essential for substrate stabilization and functional charge transfer.
Assuntos
Carboxiliases/química , Carboxiliases/metabolismo , Chlorella/enzimologia , Ácidos Graxos/metabolismo , Proteínas de Algas/química , Proteínas de Algas/metabolismo , Alcanos/metabolismo , Substituição de Aminoácidos , Aminoácidos/metabolismo , Bicarbonatos/metabolismo , Biocatálise , Dióxido de Carbono/metabolismo , Domínio Catalítico , Cristalografia por Raios X , Descarboxilação , Transporte de Elétrons , Flavina-Adenina Dinucleotídeo/química , Ligação de Hidrogênio , Luz , Modelos Moleculares , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Oxirredução , Fótons , Conformação Proteica , TemperaturaRESUMO
The effects of TLR4 blocker on blood cell morphology, concentrations proinflammatory cytokines, and functional state of the liver and kidneys were studied in outbred male rats (n=60) after intravenous injection of 20 mg/kg LPS isolated from opportunistic Proteus mirabilis strain ATCC 51393. TLR4 blocker TLR4-IN-C34 was injected intravenously in a dose of 1 mg/kg/day over 3 days. Systemic inflammatory reaction induced by LPS was characterized by elevation of serum TNFα, IL-1ß, IL-6, erythrocyte sedimentation rate, leukocytosis, and thrombocytosis. Increased activity of hepatocyte enzymes (ALT, alkaline phosphatase, and lactate dehydrogenase), retention of nitrogen metabolites (urea and creatinine), elevated content of protein oxidation products, and enhanced protein catabolism were also observed. Administration of TLR4 blocker reduced parameters of inflammatory reaction and prevented the development of hypercatabolic syndrome; endotoxicosis and kidney function indicators approached the normal levels.
Assuntos
Anti-Inflamatórios/farmacologia , Leucocitose/tratamento farmacológico , Lipopolissacarídeos/antagonistas & inibidores , Piranos/farmacologia , Sepse/tratamento farmacológico , Trombocitose/tratamento farmacológico , Receptor 4 Toll-Like/antagonistas & inibidores , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Animais , Animais não Endogâmicos , Creatinina/sangue , Modelos Animais de Doenças , Regulação da Expressão Gênica , Injeções Intravenosas , Interleucina-1beta/sangue , Interleucina-1beta/genética , Interleucina-6/sangue , Interleucina-6/genética , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , L-Lactato Desidrogenase/sangue , Leucocitose/sangue , Leucocitose/patologia , Lipopolissacarídeos/toxicidade , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Proteus mirabilis/química , Ratos , Sepse/sangue , Sepse/patologia , Transdução de Sinais , Trombocitose/sangue , Trombocitose/patologia , Receptor 4 Toll-Like/sangue , Receptor 4 Toll-Like/genética , Fator de Necrose Tumoral alfa/sangue , Fator de Necrose Tumoral alfa/genética , Ureia/sangueRESUMO
The U.S. Spallation Neutron Source (SNS) is a state-of-the-art neutron scattering facility delivering the world's most intense pulsed neutron beams to a wide array of instruments, which are used to conduct investigations in many fields of engineering, physics, chemistry, material science, and biology. Neutrons are produced by spallation of liquid Hg by the bombardment of short (â¼1 µs), intense (â¼35 A) pulses of protons delivered at 60 Hz by an accumulator ring which is fed by a high-intensity, 1 GeV, H- LINAC (linear accelerator). This facility has operated nearly continuously since 2006 but has recently undergone a 4-month maintenance period, which featured a complete replacement of the 2.5 MeV injector feeding the LINAC. The new injector was developed at ORNL in an off-line beam test facility and consists of an ion source, low energy beam transport, and a Radio Frequency Quadrupole (RFQ). This report first describes the installed configuration of the new injector detailing the ion source system. The first beam current, RFQ transmission, emittance, and energy measurements from the injector installed on the SNS are reported. These data not only show a significant performance improvement for our existing facility but will also make accessible the higher beam current requirements for future SNS upgrade projects: the proton power upgrade and second target station.
RESUMO
In this article, we consider the influence of combined general anesthesia on the results of electrically-involved stapedial reflex threshold (esrt) registration. We pay a special attention to the anesthesia to exclude its influence on the esrt. This study included 52 patients with bilateral chronic neurosensory hearing impairment. We conducted a retrospective (from 2014 to 2016) and prospective (from 2017 to 2018) analysis of anesthesia protocols. Even though the inhaled anesthesia (sevoflurane in this case) has a depressive effect on esrt registration (the higher the minimal alveolar concentration of anesthetic agent, the higher the reflex threshold), our study shows a possibility of using it in an extended anesthesia monitoring. Inclusion of myorelaxants in cochlear implantation anesthesia protocol not only provides a safe anesthesia, but also does not prevent a timely intraoperative cochlear implant testing.
Assuntos
Implante Coclear , Implantes Cocleares , Anestesia Geral , Estimulação Elétrica , Humanos , Estudos Prospectivos , Reflexo Acústico , Estudos RetrospectivosRESUMO
Aspergillosis represents a spectrum of fungal diseases which are caused by fungi of the genus Aspergillus. Animal models have been developed and used to address immune-based mechanisms of defense against these fungi. Invertebrate models enabled mass screening of virulence attributes of Aspergillus species as well as mechanisms of acquired resistance to antifungal agents. This review represents a concise view of cellular and humoral participants in an immune response to Aspergillus gained mostly from rodent models of aspergillosis. The survey of immune defense mechanisms was given, including the role of innate immune cells (macrophages, neutrophils, monocytes, eosinophils, innate-like lymphocytes) and receptors in antifungal response, the significance of dendritic cells in activation of specific adaptive T cell-mediated immune responses and the regulatory mechanisms of excessive response. Insight into innate immune defense mechanisms gained using non-vertebrate models of infections with Aspergillus sp. was given as well. The contribution of animal models to the current knowledge of immune mechanisms of resistance or susceptibility to these fungi was stressed and the significance of data gained from these models in forming the basis for the design of therapeutic strategies in prevention and/or treatment of aspergillosis was pointed out.
Assuntos
Aspergilose/imunologia , Modelos Animais de Doenças , Imunidade Inata , Animais , Antifúngicos/uso terapêutico , Aspergilose/tratamento farmacológico , Aspergillus , Suscetibilidade a Doenças , Imunidade Celular , Invertebrados , Macrófagos/imunologia , Camundongos , Neutrófilos/imunologia , VertebradosRESUMO
AIM: The study of intracardiac hemodynamics and blood flow in the pulmonary circuit in patients with community - acquired pneumonia, depending on the presence of concomitant pathology of the cardiovascular system and the severity of the pathological process. MATERIALS AND METHODS: In 43 patients with community - acquired pneumonia (22 men, 21 women, mean age 67±17 years), the functional state of pulmonary - cardiac hemodynamics was assessed by echodoplerography. All subjects were divided into 2 groups: 1st group - 25 patients with community - acquired pneumonia (mean age 49±18 years) without concomitant pathology of the cardiovascular system and 2nd group - 18 patients with community - acquired pneumonia (mean age 70.1±11 years) with concomitant cardiovascular disease. RESULTS: The main ultrasound parameters did not differ from the normal values in patients from the 1st group. In patients from the 2nd group there was a significant deterioration of several pulmonary - cardiac hemodynamics parameters, decrease of left ventricular ejection fraction, significant myocardial hypertrophy of the left ventricle and left atrium size increase. Regarding the right heart chambers it was revealed dilatation of the right ventricle, increasing of the estimated systolic pressure in the right ventricle, deterioration of right ventricle myocardial diastolic function, increase of the: RV/LV size ratio, LV eccentricity index, RV myocardium thickness, diameter of the pulmonary artery, velocity of pulmonary regurgitation and the area right atrium size. In addition, the amplitude of systolic displacement of the tricuspid valve ring and the intensity of inspiratory collapse of the inferior vena cava decreased. Correlation analysis of clinical and laboratory parameters, which are markers of endogenous intoxication, oxygen saturation of arterial blood (SpO2), separately for two groups of patients with community - acquired pneumonia, showed a reliable correlation with a number of informative and used in the practice echocardiography parameters of pulmonary cardiac hemodynamics, characterizing systolic (systolic movement amplitude of the tricuspid valve ring - TAPSE), as well as diastolic function (E/A of the right ventricle) of the heart. CONCLUSION: The relationship between the severity of pulmonary - cardiac hemodynamics disturbances in patients with community - acquired pneumonia, having comorbid pathology, contributing to the deterioration of pulmonary - cardiac hemodynamics and more severe course of the disease with markers of the inflammatory process and oxygen saturation of arterial blood decrease is revealed.
Assuntos
Infecções Comunitárias Adquiridas , Hemodinâmica/fisiologia , Pneumonia , Função Ventricular Esquerda , Adulto , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Volume SistólicoRESUMO
AIM: To assess the efficacy and safety of Arbidol in the influenza and ARVI preventing in patients with asthma and chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: This study was an open label and prospective during epidemic period of 2016-2017 years. 100 outpatients aged 18 to 80 years with verified asthma and/or COPD, were enrolled to therapy group, and received oral umifenovir 200 mg once daily for 14 days and then 200 mg twice a week for 3 weeks.The medical records data for the same epidemic period of 2016-2017 seasons of the same patients during witch they received no prophylaxis was taken as a control. The data analysis was made by applying parametric and nonparametric statistical methods. RESULTS: Seasonal and post-exposure prophylaxis using umifenovir was associated with 2.6-times reduction in influenza and ARVI morbidity compared to control. In diseased patients (ARVI) of the therapy group the number of patients with mild illness prevailed (62.2%) and was significantly differed from control (37.1%). Severity of catarrhal symptoms and intoxication, was reduced with umifenovir prophylaxis course and were mild in 67.6% and 67.6% respectively of therapy group compared with 43.3% and 46.4% of control. Influenza and ARVI complications were only detected in control group (4 cases). The percentage of patients with incidents of underlying disease exacerbation was 42% in therapy group and 93% in control group. Also, exacerbation in the therapy group were mild in 59.5% and 34.4% in control group, while moderate exacerbation prevailed in control group and was in 59.1% of cases with was significantly higher then in therapy group (39.3%). Results in more frequent use of adjuvant in the control group compared with the therapy group (81.7% and 59.5% respectively). Patients of control group had a higher risk of hospitalizations due to underlying disease aggravation (11.8%), compared with therapy group (9.5%) but these differences were not significant. CONCLUSION: Seasonal and post-exposure prophylaxis with Arbidol reduce influenza and ARVI morbidity in patients with asthma and COPD during epidemic period, frequency and severity of chronic obstructive pulmonary disease aggravations resulting in decrease in the number of hospitalizations. Also, prophylaxis with Arbidol reduced the severity of catarrhal symptoms and intoxication.
Assuntos
Antivirais/uso terapêutico , Asma/prevenção & controle , Indóis/uso terapêutico , Influenza Humana/prevenção & controle , Doença Pulmonar Obstrutiva Crônica/prevenção & controle , Infecções Respiratórias/prevenção & controle , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antivirais/administração & dosagem , Asma/virologia , Progressão da Doença , Humanos , Indóis/administração & dosagem , Influenza Humana/virologia , Pessoa de Meia-Idade , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/virologia , Infecções Respiratórias/virologia , Adulto JovemRESUMO
Modern achievements of technical progress, in particular additive technologies (ATs) and three-dimensional printing, have been increasingly introduced in neurosurgical practice. The increasing complexity of surgical interventions requires thorough planning of surgery and a high level of training of young neurosurgeons. Creation of full-scale three-dimensional models for planning of surgery enables visualization of the anatomical region of interest. Additive technologies are especially extensively used in reconstructive surgery of skull defects. ATs enable fast and efficient solving of the following tasks: - generation of accurate models of the skull and an implant; - development and fabrication of individual molds for intraoperative formation of implants from polymeric two-component materials (e.g., PMMA); - fabrication of individual implants from titanium alloys or polyetheretherketone (PEEK) for further use in surgery.
Assuntos
Procedimentos de Cirurgia Plástica , Procedimentos Neurocirúrgicos , Impressão Tridimensional , Próteses e Implantes , CrânioRESUMO
The authors assessed efficacy and safety of the operation of plication of deep veins of lower extremities, pelvic veins, and the inferior vena cava as a method of preventing fatal pulmonary artery thromboembolism. A total of 48 patients were operated on. Of these, 23 patients belonged to traumatological-and-orthopaedical cohort, 3 to general surgical cohort, 4 to gynaecological, and 18 to vascular cohort (isolated deep vein thrombosis). The length of the floating head of the thrombus varied from 2 to 10 cm. The presence of a floating thrombus in traumatological, surgical and gynaecological patients, regardless of the length of the floating part was an absolute indication for thrombectomy and venous plication. Vascular patients were operated on in accordance with the National Guidelines (with the length of the thrombus floating portion of not less than 4 cm). In all cases, surgical management envisaged direct and indirect thrombectomy. Plication was always performed above the level of venotomy. It was shown that thrombectomy combined with plication of major veins is a reliable and safe method of prophylaxis, being in some cases the only possible method of preventing fatal pulmonary artery thromboembolism. The operation of plication makes it possible not to cancel a scheduled surgical intervention in patients with a detected floating thrombus of major veins. The operation of thrombectomy and plication above the level of the floating head of the thrombus may be considered an operation of choice in the conditions where there is no possibility to use endovascular methods of treatment (implantation of a cava filter, endovascular catheter thrombectomy), as well as in pregnant women. Restoration of the venous lumen occurs at safe terms spontaneously, not requiring repeat surgical intervention. Simultaneous plication of the vein does not complicate the course of the postoperative period of the main surgical intervention. Thrombectomy and plication do not lead to the development of severe chronic venous insufficiency.
Assuntos
Complicações Pós-Operatórias/prevenção & controle , Embolia Pulmonar , Insuficiência Venosa , Trombose Venosa , Adulto , Idoso , Feminino , Humanos , Veia Ilíaca/patologia , Veia Ilíaca/cirurgia , Extremidade Inferior/irrigação sanguínea , Masculino , Pessoa de Meia-Idade , Gravidez , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/etiologia , Embolia Pulmonar/prevenção & controle , Estudos Retrospectivos , Federação Russa , Trombectomia/métodos , Tomografia Computadorizada por Raios X , Ultrassonografia Doppler Dupla/métodos , Veia Cava Inferior/patologia , Veia Cava Inferior/cirurgia , Insuficiência Venosa/etiologia , Insuficiência Venosa/prevenção & controle , Trombose Venosa/complicações , Trombose Venosa/diagnóstico , Trombose Venosa/cirurgiaRESUMO
UNLABELLED: The methods for the rehabilitative treatment play an important role in the management of the patients presenting with the diseases of the musculoskeletal system. One of these techniques is chronomagnetic therapy. AIM: The objective of the present study was to evaluate the influence of chronomagnetic therapy on the patient's quality of life. PATIENTS AND METHODS: The patients of the main group included 30 ones with osteoarthrosis, 30 with rheumatoid arthritis, 20 with ankylosing spondylitis, 6 with podagric arthritis, 6 with psoriatic arthritis, and 6 others with reactive arthritis. Each of these patients every day underwent 10 sessions of chronomagnetic therapy with the use of the Multimag apparatus («Kasimov Instrumental Plant¼, Ryazan). The patients of the comparison group (20 ones presenting with osteoarthrosis, 27 with rheumatoid arthritis, 15 with ankylosing spondylitis, 4 with podagric arthritis, 4 with psoriatic arthritis, and 4 subjects with reactive arthritis) received the identical chronomagnetotherapeutic treatment under the conditions of the «Vulan¼ balneological health resort located at Gelendzhik, Krasnodar Region. RESULTS: The patients of the main group presenting with osteoarthrosis were characterized by the most pronounced manifestations of the role physical and social behaviour and the associated enhancement of pain intensity. The patients with rheumatoid arthritis exhibited well apparent manifestation of role and emotional functioning as well as enhanced vitality. Positive dynamics of these characteristics (role physical and emotional functioning, vital activity) was documented in the patients of the comparison group presenting with osteoarthrosis, ankylosing spondylitis, and rheumatoid arthritis. In this group, the patients with osteoarthrosis, ankylosing spondylitis, and rheumatoid arthritis experienced the improvement of the major parameters of the quality of life characterizing the physical and mental components of the health status. CONCLUSION: The chronomagnetotherapeutic treatment at the stage of rehabilitation of the patients suffering from the diseases of the musculoskeletal system markedly improves the characteristics of physical health the disturbances of which may lead to the development of psycho-somatic disorders. Chronomagnetic therapy of the patients with the diseases of the musculoskeletal system under the conditions of a balneological health resort proved to be more effective in terms of improvement of the parameters of physical and mental health. The result of the subjective evaluation of the health status in such patients can be used as a marker of the effectiveness of chronomagnetic therapy and an indicator of remission of the disease.
Assuntos
Balneologia/métodos , Cronoterapia/métodos , Estâncias para Tratamento de Saúde , Magnetoterapia/métodos , Doenças Musculoesqueléticas/reabilitação , Qualidade de Vida , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The Oak Ridge National Laboratory operates the Spallation Neutron Source, consisting of a H(-) ion source, a 1 GeV linac and an accumulator ring. The accumulated <1 µs-long, â¼35 A beam pulses are extracted from the ring at 60 Hz and directed onto a liquid Hg target. Spalled neutrons are directed to â¼20 world class instruments. Currently, the facility operates routinely with â¼1.2 MW of average beam power, which soon will be raised to 1.4 MW. A future upgrade with a second target station calls for raising the power to 2.8 MW. This paper describes the status of two accelerator components expected to play important roles in achieving these goals: a recently acquired RFQ accelerator and the external antenna ion source. Currently, the RFQ is being conditioned in a newly constructed 2.5 MeV Integrated Test Facility (ITF) and the external antenna source is also being tested on a separate test stand. This paper presents the results of experiments and the testing of these systems.
RESUMO
A review of documents on the peculiarities of obstetric and gynecological care in besieged Leningrad is presented with special reference to the data about the number of children born during blockade and their health status in the first months of life, the work of maternity hospitals, their number and personnel. The term «military time amenorrhea¼ coined during blockade is discussed.
Assuntos
Ginecologia/história , Obstetrícia/história , II Guerra Mundial , História do Século XX , Humanos , Federação RussaRESUMO
In this study, we investigated a question about a possibility to form involuntary auditory-visual associations in children (8-11 yrs) during discriminations of speech sounds (phonemes) when they presented simultaneously with visual stimuli. It was used two types of static images - geometrical figures and images of hand gestures. We judge about the formation of auditory-visual association by behavioral disturbance (reaction time, percentage of wrong reactions during discriminations of phonemes) after changes in experimental protocol viz, partial substitution of preceding pairs of stimuli which were used during training to form auditory-visual associations for the new combinations of previous images and sounds. We find that in research conditions comparatively fast formed pronounced auditory-visual association; however features of response to mismatch stimuli in comparison with adults make to suggest the relative immaturity ofneurons of social perception in children.
Assuntos
Reconhecimento Psicológico , Percepção da Fala , Percepção Visual , Estimulação Acústica , Adolescente , Criança , Discriminação Psicológica , Lateralidade Funcional , Humanos , Leitura Labial , Mascaramento Perceptivo , Estimulação LuminosaRESUMO
The aim of our study was to examine the effect of cognitive load on the development of muscle fatigue. Sub- jects performed 250 maximal compressions of a handgrip dynamometer in response to the target acoustic stimulus. Stimuli were presented in three paradigms with different levels of cognitive load: (1) the reaction task with one type of signals (2) the acoustic stimuli recognition task with the 50% target and 50% non-target stimuli, where voluntary attention was involved, (3) the recognition task with the 17% target and 83% non tar- get stimuli, that led to the activation of voluntary and involuntary attention systems. As fatigue indicators amplitude of compression force in response to the target stimulus, the maximum voluntary contraction and rating of perceived exertion were used. Our results showed the reduced level of fatigue in experiment with the activation of voluntary and involuntary attention systems. Moreover, the activation of involuntary attention, accompanied by mismatch negativity in the EEG, enhanced the effect of voluntary attention.
Assuntos
Atenção/fisiologia , Cognição/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Reconhecimento Fisiológico de Modelo/fisiologia , Estimulação Acústica , Adulto , Eletroencefalografia , Eletromiografia , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Músculo Esquelético/inervaçãoRESUMO
The present study is designed to establish how lexical frequency of Russian words influences the acoustic mismatch negativity (MMN) latency and amplitude. The event related potentials (ERP) were recorded according to the multi-deviant passive odd-ball paradigm by using Russian words with different lexical frequencies and pseudowords. We found that the high-frequency words presentation led to a significantly more pronounced MMN response relative to the low-frequency one. The high-frequency words also evoked an earlier response, indicating more rapid access to a frequently used lexical entry. We suggest that a more pronounced amplitude and an earlier latency of acoustic MMN of high-frequency versus low-frequency items is a result of the word memory traces activation as more strongly connected assemblies of neurons. The MMN amplitude and latency for words were partly matched with the MMN for pseudowords (the analog of high-frequency word evoked the most pronounced response and the analog of low-frequency word evoked the weakest response), but the MMN amplitude and latency for pseudowords were significantly more pronounced and longer. We interpret this as evidence that processing of meaningless or unknown items is longer and their discrimination is more late and inaccurate than the discrimination of meaningful and frequently activated language elements.
Assuntos
Potenciais Evocados Auditivos/fisiologia , Idioma , Percepção da Altura Sonora/fisiologia , Percepção da Fala/fisiologia , Adulto , Feminino , Humanos , MasculinoRESUMO
Emotionally evoked physiological tremor dynamics was investigated on varying stimulus efficiency. Experimental protocol includes randomized presentation of four variant visual stimuli, one of the followed - subject's second name, random shuffled letters of second name, graphic representation of simple arithmetic expression with correct or incorrect answer. The physiological tremor acquisition was implemented by 3-axial digital accelerometers, fixed on external side of index fingers. The data analysis explained unconscious psychomotor activity dynamics under emotional status transitions. Evoked reactions specificity gives an opportunity to suppose stimulus-dependent lateralization of unconscious motor responses. Valid differences of the right hand psychomotor reactions were achieved for the most emotionally loaded stimulus - second name.
Assuntos
Emoções , Agitação Psicomotora/fisiopatologia , Tremor/fisiopatologia , Percepção Visual , Adulto , Feminino , Humanos , MasculinoRESUMO
The aim of the study was to investigate the influence of central fatigue and motor activity on sensory gating characteristics. The P50 component in a standard paired-click paradigm was used as a sensory gating index. The main attention was devoted to the P50 peak latency change in the fatigue development. It was found that the sustained muscle load leading to the fatigue development significantly reduced sensory gating and the P50 peak latency in response to the second stimulus of the pair. This may be due to the inhibitory process suppression underlying the sensory gating in the development of central fatigue.