Evaluating peripheral neuromuscular function with brief movement-evoked pain.

Movement-evoked pain is an understudied manifestation of musculoskeletal conditions that contributes to disability, yet little is known about how the neuromuscular system responds to movement-evoked pain. The present study examined whether movement-evoked pain impacts force production, electromyographic (EMG) muscle activity, and the rate of force development (RFD) during submaximal muscle contractions. Fifteen healthy adults (9 males; age = 30.3 ± 10.2 yr, range = 22-59 yr) performed submaximal isometric first finger abduction contractions without pain (baseline) and with movement-evoked pain induced by laser stimulation to the dorsum of the hand. Normalized force (% maximal voluntary contraction) and RFD decreased by 11% (P < 0.001) and 15% (P = 0.003), respectively, with movement-evoked pain, without any change in normalized peak EMG (P = 0.77). Early contractile RFD, force impulse, and corresponding EMG amplitude computed within time segments of 50, 100, 150, and 200 ms relative to the onset of movement were also unaffected by movement-evoked pain (P > 0.05). Our results demonstrate that movement-evoked pain impairs peak characteristics and not early measures of submaximal force production and RFD, without affecting EMG activity (peak and early). Possible explanations for the stability in EMG with reduced force include antagonist coactivation and a reorganization of motoneuronal activation strategy, which is discussed here.NEW & NOTEWORTHY We provide neurophysiological evidence to indicate that peak force and rate of force development are reduced by movement-evoked pain despite a lack of change in EMG and early rapid force development in the first dorsal interosseous muscle. Additional evidence suggests that these findings may coexist with a reorganization in motoneuronal activation strategy.

Highly crystalline and fluorescent BODIPY-labelled phenyl-triazole-coumarins as n-type semiconducting materials for OFET devices.

In this work, the synthesis of BODIPY-phenyl-triazole labelled coumarins (BPhTCs) using a two-step approach is described. The influence of the BODIPY appending on the photophysical, electrochemical and thermal properties of the phenyl-triazole-coumarin precursors (PhTCs) was investigated. Band gap energies were measured by absorption spectroscopy (2.20 ± 0.02 eV in the solid and 2.35 ± 0.01 eV in solution) and cyclic voltammetry (2.10 ± 0.05 eV). The results are supported by DFT calculations confirming the presence of lowest LUMO levels that facilitate the electron injection and stabilize the electron transport. Their charge-transport parameters were measured in Organic Field-Effect Transistor (OFET) devices. BPhTCs showed an ambipolar transistor behavior with good n-type charge mobilities (10-2 cm2V-1s-1) allowing these derivatives to be employed as promising semiconducting crystalline and fluorescent materials with good thermal and air stability up to 250 °C.

Synthesis, and evaluation of photophysical properties of a potential DPP-derived photosensitizer for photodynamic therapy with D-A-D architecture.

The study of a macromolecule derived from DPP and triphenylamine, (DPP-BisTPA) by computational chemistry, its synthesis by direct arylation, optical characterization (UV-Vis and fluorescence) and electrochemistry (cyclic voltammetry), as well as its evaluation as a generator of reactive oxygen species indirectly, through the degradation of uric acid. The results obtained by DFT using B3LYP/6-31G (d, p) and TD-DFT using CAM-B3LYP/6-31G (d, p) reveal values of energy levels of the first singlet and triplet excited state that indicate a possible intersystem crossover and the possible generation of reactive oxygen species by a type I mechanism. The compound presents an absorption region within the phototherapeutic window. The electrochemical bandgap is 1.64 eV which suggests a behavior as a semiconductor. DPP-BisTPa were processed as hemispherical nanoparticles with a size around 100 nm, and NPOs were evaluated as a photosensitizer with a ROS generation yield of 4% using a photodynamic therapy flashlight as the light source.

Changes in EEG alpha-band power during prehension indicates neural motor drive inhibition.

Changes in alpha band activity (8-12 Hz) indicate the downregulation of brain regions during cognitive tasks, reflecting real-time cognitive load. Despite this, its feasibility to be used in a more dynamic environment with ongoing motor corrections has not been studied. This research used electroencephalography (EEG) to explore how different brain regions are engaged during a simple grasp and lift task where unexpected changes to the object's weight or surface friction are introduced. The results suggest that alpha activity changes related to motor error correction occur only in motor-related areas (i.e. central areas) but not in error processing areas (i.e., frontoparietal network) during unexpected weight changes. This suggests that oscillations over motor areas reflect the reduction of motor drive related to motor error correction, thus, being a potential cortical electrophysiological biomarker for the process and not solely as a proxy for cognitive demands. This observation is particularly relevant in scenarios where these signals are used to evaluate high cognitive demands co-occurring with high levels of motor errors and corrections, such as prosthesis use. The establishment of electrophysiological biomarkers of mental resource allocation during movement and cognition can help identify indicators of mental workload and motor drive, which may be useful for improving brain-machine interfaces.NEW & NOTEWORTHY We demonstrated that alpha suppression, an EEG phenomenon with high temporal resolution, occurs over the primary sensorimotor area during error correction during lift movements. Interpretations of alpha activity are often attributed to high cognitive demands, thus recognizing that it is also influenced by motor processes is important in situations where cognitive demands are paired with movement errors. This could further have application as a biomarker for error correction in human-machine interfaces, such as neuroprostheses.

Synthesis and Study of the Optical Properties of a Conjugated Polymer with Configurational Isomerism for Optoelectronics.

A π-conjugated polymer (PBQT) containing bis-(2-ethylhexyloxy)-benzo [1,2-b'] bithiophene (BDT) units alternated with a quinoline-vinylene trimer was obtained by the Stille reaction. The chemical structure of the polymer was verified by nuclear magnetic resonance (1H NMR), Fourier transform infrared (FT-IR), and mass spectroscopy (MALDI-TOF). The intrinsic photophysical properties of the solution were evaluated by absorption and (static and dynamic) fluorescence. The polymer PBQT exhibits photochromism with a change in absorption from blue (449 nm) to burgundy (545 nm) and a change in fluorescence emission from green (513 nm) to orange (605 nm) due to conformational photoisomerization from the trans to the cis isomer, which was supported by theoretical calculations DFT and TD-DFT. This optical response can be used in optical sensors, security elements, or optical switches. Furthermore, the polymer forms spin-coated films with absorption properties that cover the entire visible range, with a maximum near the solar emission maximum. The frontier molecular orbitals, HOMO and LUMO, were calculated by cyclic voltammetry, and values of -5.29 eV and -3.69, respectively, and a bandgap of 1.6 eV were obtained, making this material a semiconductor with a good energetic match. These properties could suggest its use in photovoltaic applications.

Pain-related gamma band activity is dependent on the features of nociceptive stimuli: a comparison of laser and contact heat.

Painful contact heat and laser stimulation offer an avenue to characterize nociceptive pathways involved in acute pain processing, by way of evoked potentials. Direct comparisons of radiant laser and contact heat are limited, particularly in context of examining time-frequency responses to stimulation. This is important in light of recent evidence to suggest that gamma band oscillations (GBOs) represent a functionally heterogeneous measure of pain. The purpose of the current study was to investigate differences in GBOs generated in response to laser and contact heat stimulation of the nondominant forearm. Following intensity matching to pain ratings, evoked electroencephalography (EEG) responses to laser and contact heat stimulation were examined in the time-frequency domain in the same participants (19 healthy adults) across two sessions. At ∼200 ms, both contact heat and laser stimulation resulted in significant, group-level event-related synchronization (ERS) in the low gamma band (i.e., 30-60 Hz) in central electrode locations (Cc, Cz, Ci). Laser stimulation also generated ERS in the 60-100 Hz range (i.e., high gamma), at ∼200 ms, while contact heat led to a significant period of desynchronization in the high gamma range between 400 and 600 ms. Both contact heat and laser GBOs were stronger on the central electrodes contralateral to the stimulated forearm, indicative of primary somatosensory cortex involvement. Based on our findings, and taken in conjunction with previous studies, laser and contact heat stimulation generate characteristically different responses in the brain, with only the former leading to high-frequency GBOs characteristic of painful stimuli.NEW & NOTEWORTHY Despite matching pain perception between noxious laser and contact heat stimuli, we report notable differences in gamma band oscillations (GBO), measured via electroencephalography. GBOs produced following contact heat more closely resembled that of nonnoxious stimuli, while GBOs following laser stimuli were in line with previous reports. Taken together, laser and contact heat stimulation generate characteristically different responses in the brain, with only the former leading to high-frequency GBOs characteristic of painful stimuli.

Tumor de músculo liso uterino de potencial maligno incierto (STUMP): reporte de caso y revisión de la literatura / Uterine smooth muscle tumor of uncertain malignant potential (STUMP): case report and literature review

Myometrial smooth muscle neoplasms are the most common gynecologic tumors with a prevalence of 70-80% at age 50. Among women undergoing hysterectomy or myomectomy for a suspected diagnosis of leiomyoma, 0.01% receive a diagnosis of STUMP. Clinically, the average age of presentation is between 41-48 years. Tumors ranging from 3 to 30 cm have been described. Signs and symptoms are similar to leiomyomas, such as abnormal uterine bleeding, anemia, dysmenorrhea, pelvic pain, pelvic mass, infertility or other types of pain secondary to compression of adjacent organs. Due to the limited literature available, there is no definite management consensus, and treatment and follow-up options are limited to observational studies. The standard treatment is total hysterectomy with or without bilateral salpingo-oophorectomy; if fertility has already been completed, there is no role for adjuvant hormonal therapy or chemotherapy. The overall 5-year survival is 92-100%. A case of a 31-year-old woman with STUMP is presented.

Tumor de células epitelioides perivasculares (PEComa) uterino en una paciente pediátrica: reporte de caso / Uterine perivascular epithelioid cell tumor (PEComa) in a pediatric patient: case report

El PEComa es un tumor de células epitelioides, perivascular, de origen mesenquimatoso. Estos tumores corresponden a un grupo raro de neoplasias. Hay cerca de 100 casos reportados de los que solo el 30% son de origen ginecológico y el cuerpo uterino es el sitio más frecuente. Debido a su baja frecuencia de aparición no hay una conducta médica y tratamiento establecidos, por lo cual es un reto el manejo de esta entidad. La presentación en población pediátrica es extremadamente rara, con datos limitados de su frecuencia de presentación en este grupo etario. Presentamos el caso de una paciente de 13 años que consultó por dolor pélvico; se realizaron imágenes diagnósticas que documentaron una masa paraanexial derecha sólida; es llevada a cirugía obteniendo como hallazgo un tumor dependiente del cuerpo uterino cuya histología correspondía a un PEComa con características de comportamiento maligno

PEComa is a perivascular epithelioid cell tumor of mesenchymal origin. These tumors correspond to a rare group of neoplasms. About 100 cases have been reported, of which only 30% are of gynecological origin, and the uterine body is the most frequent site. Due to its low frequency of appearance, there is no established medical conduct and treatment, which is why the management of this entity is a challenge. Presentation in the pediatric population is extremely rare, with limited data on its frequency in this age group. We present the case of a 13-year-old patient who consulted for pelvic pain. Diagnostic images were performed that documented a solid right para-adnexal mass. She was taken to surgery, which evidenced a tumor dependent on the uterine body with histology corresponding to a PEComa with characteristics of malignant behavior

3-(4-Formylphenyl)-triazole functionalized coumarins as violet-blue luminophores and n-type semiconductors: synthesis, photophysical, electrochemical and thermal properties.

3-(4-Formylphenyl)-triazole-coumarin hybrid chromophores (FPhTCs) were synthesized in good yields, using a click chemistry protocol, and were also structurally characterized. Their photophysical, electrochemical and thermal properties were measured demonstrating that FPhTCs are luminescent in the blue-violet region of the electromagnetic spectrum, both in solution and the solid state. They showed an electrochemical band-gap values of 2.79 ± 0.08 eV, resistivity values between 104 and 105 Ω cm and are thermally stable up to 225 °C, properties that promise FPhTCs as good candidates for optoelectronic or imaging applications. Their solution and solid state photoluminescent properties are discussed and supported by theoretical calculations.

Psychosis in Parkinson's Disease: Looking Beyond Dopaminergic Treatments.

BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide. The symptoms of PD are characterized not only by motor alterations but also by a spectrum of nonmotor symptoms. Some of these are psychiatric manifestations such as sleep disorders; depression; cognitive difficulties that can evolve into dementia; and symptoms of psychosis, which include hallucinations, illusions, and delusions. Parkinson's disease psychosis (PDP) occurs in 18-50% of patients with PD. Treating PDP is challenging because antipsychotic drugs tend to be inefficient or may even worsen the disease's motor symptoms. OBJECTIVE: This review aims to summarize the current understanding of the molecular mechanisms involved in PDP and recent innovative alternatives for its treatment. METHODS: This is a narrative review in which an extensive literature search was performed on the Scopus, EMBASE, PubMed, ISI Web of Science, and Google Scholar databases from inception to August 2021. The terms "Parkinson's disease psychosis", "Parkinson psychosis," "neurodegenerative psychosis", and "dopamine psychosis" were among the keywords used in the search. RESULTS: Recently, views on the etiology of hallucinations and illusions have evolved remarkably. PDP has been cemented as a multifactorial entity dependent on extrinsic and novel intrinsic mechanisms, including genetic factors, neurostructural alterations, functional disruptions, visual processing disturbances, and sleep disorders. Consequently, innovative pharmacological and biological treatments have been proposed. Pimavanserin, a selective 5-HT2A inverse agonist, stands out after its approval to treat PDP-associated hallucinations and illusions. CONCLUSION: Future results from upcoming clinical trials should further characterize the role of this drug in the management of PDP as well as other treatment options with novel mechanisms of action, such as saracatinib, SEP-363856, cannabidiol, electroconvulsive therapy, and transcranial magnetic stimulation.

Effect of Biochar from Oat Hulls on the Physical Properties of Asphalt Binder.

The purpose of this study was to verify the feasibility of using biochar from oat hulls (BO) as a potential bio-modifier to improve the physical properties of conventional asphalt binder. The BO and asphalt binder were characterized by confocal (fluorescence) laser microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. Then, an asphalt binder modification procedure was established and modifications with 2.5, 5.0 and 7.5% of BO on the weight of the asphalt binder were evaluated, using a particle size < 75 µm. The physical properties of the evaluated modified asphalt binder with BO were: rotational viscosity in original and aged state, aging index, Fraass breaking point, softening point, penetration, penetration rate and storage stability. The results indicated that the BO has a porous structure, able to interact with the asphalt binder by C=O and C=C bonds. In addition, modification of the asphalt binder with BO increases the rotational viscosity related to high-temperature rutting resistance. The results obtained from the Fraass breaking point and softening point indicated that the use of BO extends the viscoelastic range of the asphalt binder. In addition, the evaluated modifications present low susceptibility to aging and good storage stability.

Supraspinal facilitation to repetitive painful stimulation: a laser-evoked potential study.

To better characterize central modulation mechanisms involved in the processing of daily repetitive painful stimulation, laser-evoked potentials (LEPs) were recorded at and away from the conditioning area in healthy participants. In addition, we aimed to evaluate a repetitive painful stimulation paradigm that could be conducted in a shorter time frame than previous studies. Collectively, continuous pain rating, warm and heat pain threshold results suggest that sensitivity to pain was reduced 24 h after the shortened repeated painful stimulation. Laser-evoked potentials revealed a significant increase in the contralateral arm to where the conditioning stimulus was applied. This finding was specific to noxious conditioning (i.e., not seen in the control brush experiment). These results provide neurophysiological evidence of pain facilitation resulting from prolonged exposure to painful heat, potentially arising in supraspinal structures.NEW & NOTEWORTHY We provide evidence for supraspinal faciliation measured via laser-evoked potentails in response to a shortened and methodologically improved repetitive painful stimulation paradigm, serving the broader scientific community, insofar as providing a paradigm can feasibly be completed in a caldendar week. These findings provide new evidence using laser-evoked potentials indicating increased activation of the anterior cingulate cortex during prolonged pain processing.

Electroconvulsive Therapy in Psychiatric Disorders: A Narrative Review Exploring Neuroendocrine-Immune Therapeutic Mechanisms and Clinical Implications.

Electroconvulsive therapy (ECT) is based on conducting an electrical current through the brain to stimulate it and trigger generalized convulsion activity with therapeutic ends. Due to the efficient use of ECT during the last years, interest in the molecular bases involved in its mechanism of action has increased. Therefore, different hypotheses have emerged. In this context, the goal of this review is to describe the neurobiological, endocrine, and immune mechanisms involved in ECT and to detail its clinical efficacy in different psychiatric pathologies. This is a narrative review in which an extensive literature search was performed on the Scopus, Embase, PubMed, ISI Web of Science, and Google Scholar databases from inception to February 2022. The terms "electroconvulsive therapy", "neurobiological effects of electroconvulsive therapy", "molecular mechanisms in electroconvulsive therapy", and "psychiatric disorders" were among the keywords used in the search. The mechanisms of action of ECT include neurobiological function modifications and endocrine and immune changes that take place after ECT. Among these, the decrease in neural network hyperconnectivity, neuroinflammation reduction, neurogenesis promotion, modulation of different monoaminergic systems, and hypothalamus-hypophysis-adrenal and hypothalamus-hypophysis-thyroid axes normalization have been described. The majority of these elements are physiopathological components and therapeutic targets in different mental illnesses. Likewise, the use of ECT has recently expanded, with evidence of its use for other pathologies, such as Parkinson's disease psychosis, malignant neuroleptic syndrome, post-traumatic stress disorder, and obsessive-compulsive disorder. In conclusion, there is sufficient evidence to support the efficacy of ECT in the treatment of different psychiatric disorders, potentially through immune, endocrine, and neurobiological systems.

Factors associated to the duration of COVID-19 lockdowns in Chile.

During the first year of the COVID-19 pandemic, several countries have implemented non-pharmacologic measures, mainly lockdowns and social distancing, to reduce the spread of the SARS-CoV-2 virus. These strategies varied widely across nations, and their efficacy is currently being studied. This study explores demographic, socioeconomic, and epidemiological factors associated with the duration of lockdowns applied in Chile between March 25th and December 25th, 2020. Joint models for longitudinal and time-to-event data were used. In this case, the number of days under lockdown for each Chilean commune and longitudinal information were modeled jointly. Our results indicate that overcrowding, number of active cases, and positivity index are significantly associated with the duration of lockdowns, being identified as risk factors for longer lockdown duration. In short, joint models for longitudinal and time-to-event data permit the identification of factors associated with the duration of lockdowns in Chile. Indeed, our findings suggest that demographic, socioeconomic, and epidemiological factors should be used to define both entering and exiting lockdown.

Psycho-Neuro-Endocrine-Immunological Basis of the Placebo Effect: Potential Applications beyond Pain Therapy.

The placebo effect can be defined as the improvement of symptoms in a patient after the administration of an innocuous substance in a context that induces expectations regarding its effects. During recent years, it has been discovered that the placebo response not only has neurobiological functions on analgesia, but that it is also capable of generating effects on the immune and endocrine systems. The possible integration of changes in different systems of the organism could favor the well-being of the individuals and go hand in hand with conventional treatment for multiple diseases. In this sense, classic conditioning and setting expectations stand out as psychological mechanisms implicated in the placebo effect. Recent advances in neuroimaging studies suggest a relationship between the placebo response and the opioid, cannabinoid, and monoaminergic systems. Likewise, a possible immune response conditioned by the placebo effect has been reported. There is evidence of immune suppression conditioned through the insular cortex and the amygdala, with noradrenalin as the responsible neurotransmitter. Finally, a conditioned response in the secretion of different hormones has been determined in different studies; however, the molecular mechanisms involved are not entirely known. Beyond studies about its mechanism of action, the placebo effect has proved to be useful in the clinical setting with promising results in the management of neurological, psychiatric, and immunologic disorders. However, more research is needed to better characterize its potential use. This review integrates current knowledge about the psycho-neuro-endocrine-immune basis of the placebo effect and its possible clinical applications.

Modification of the Luedeking and Piret model with a delay time parameter for biotechnological lactic acid production.

OBJECTIVES: To obtain a mathematical model that adequately describes the time lag between biomass generation and lactic acid production of lactic fermentations. METHODS: Seven experimental kinetics from other research works were studied to validate our proposal: four studies of Fungal Submerged Fermentation and three cases of Bacterial Submerged Fermentation, including the data recollected by Luedeking and Piret. RESULTS: We introduce a modification to the Luedeking and Piret model that consist in the introduction of a time delay parameter in the model, this parameter would account for the lag time that exists between the production of biomass and lactic acid. It is possible to determine this time delay in a simple way by approximating the biomass and product formation considering that they behave as a first order plus dead time system. The duration of this phenomenon, which is not described with the classical Luedeking and Piret model, is a function of microorganism physiology (ease of biomass growth), environment (nutrients) and type of inoculum. CONCLUSION: The Luedeking and Piret with delay model applications reveal an increase of the R2 in all cases, evidencing the quality of fit and the simplicity of the method proposed. These model would improve the accuracy of bioprocess scaling up.

Learning to stand with unexpected sensorimotor delays.

Human standing balance relies on self-motion estimates that are used by the nervous system to detect unexpected movements and enable corrective responses and adaptations in control. These estimates must accommodate for inherent delays in sensory and motor pathways. Here, we used a robotic system to simulate human standing about the ankles in the anteroposterior direction and impose sensorimotor delays into the control of balance. Imposed delays destabilized standing, but through training, participants adapted and re-learned to balance with the delays. Before training, imposed delays attenuated vestibular contributions to balance and triggered perceptions of unexpected standing motion, suggesting increased uncertainty in the internal self-motion estimates. After training, vestibular contributions partially returned to baseline levels and larger delays were needed to evoke perceptions of unexpected standing motion. Through learning, the nervous system accommodates balance sensorimotor delays by causally linking whole-body sensory feedback (initially interpreted as imposed motion) to self-generated balance motor commands.

When standing, neurons in the brain send signals to skeletal muscles so we can adjust our movements to stay upright based on the requirements from the surrounding environment. The long nerves needed to connect our brain, muscles and sensors lead to considerable time delays (up to 160 milliseconds) between sensing the environment and the generation of balance-correcting motor signals. Such delays must be accounted for by the brain so it can adjust how it regulates balance and compensates for unexpected movements. Aging and neurological disorders can lead to lengthened neural delays, which may result in poorer balance. Computer modeling suggests that we cannot maintain upright balance if delays are longer than 300-340 milliseconds. Directly assessing the destabilizing effects of increased delays in human volunteers can reveal how capable the brain is at adapting to this neurological change. Using a custom-designed robotic balance simulator, Rasman et al. tested whether healthy volunteers could learn to balance with delays longer than the predicted 300-340 millisecond limit. In a series of experiments, 46 healthy participants stood on the balance simulator which recreates the physical sensations and neural signals for balancing upright based on a computer-driven virtual reality. This unique device enabled Rasman et al. to artificially impose delays by increasing the time between the generation of motor signals and resulting whole-body motion. The experiments showed that lengthening the delay between motor signals and whole-body motion destabilized upright standing, decreased sensory contributions to balance and led to perceptions of unexpected movements. Over five days of training on the robotic balance simulator, participants regained their ability to balance, which was accompanied by recovered sensory contributions and perceptions of expected standing, despite the imposed delays. When a subset of participants was tested three months later, they were still able to compensate for the increased delay. The experiments show that the human brain can learn to overcome delays up to 560 milliseconds in the control of balance. This discovery may have important implications for people who develop balance problems because of older age or neurologic diseases like multiple sclerosis. It is possible that robot-assisted training therapies, like the one in this study, could help people overcome their balance impairments.

The bilateral limb deficit (BLD) phenomenon during leg press: a preliminary investigation into central and peripheral factors.

BACKGROUND: The bilateral limb deficit (BLD) phenomenon suggests that lower forces are produced with bilateral limb contractions compared to the summed force produced when the same muscles are contracted unilaterally. While interhemispheric inhibition has been suggested as a cause of BLD, the origin of the deficit is yet to be determined. The aim of this study was to investigate central and peripheral factors responsible for the BLD during leg press using surface electromyography (EMG) and electroencephalography (EEG). METHODS: Fourteen adults (age = 23.7 ± 4.7 years old) completed bilateral (BL), unilateral left (UL) and unilateral right (UR) isometric leg press exercises. Bilateral limb ratio (BLR) was calculated similar to previous studies and surface EMG from three muscles of the quadriceps femoris (vastus lateralis, vastus medialis and rectus femoris) was used to measure the level of muscle activation. Movement related cortical potentials (MRCPs) over the left and right motor cortex areas (C3 and C4, respectively) were used to assess brain activity asymmetries reflecting central factors. RESULTS: No significant difference was noted in the mean BLR (BLR = 94.8%), but a subset of ten participants did demonstrate a BLD (BLR = 81.4%, p < 0.01). Mean differences in relative activation were found among the three quadricep muscles (p < 0.001) with the right VM having significantly higher amplitude for the unilateral right (0.347 ± 0.318 mV) and bilateral right (0.436 ± 0.470 mV) conditions, respectively) than either the VL or RF (p < 0.05). The VL had significantly lower amplitudes in all conditions (0.127 ± 0.138 mV; 0.111 ± 0.104 mV; 0.120 ± 0.105 mV; 0.162 ± 0.147 mV for unilateral left, bilateral left, unilateral right, and bilateral right, respectively). However no overall significant differences were noted between bilateral and unilateral conditions. No significant differences in MRCPs were observed between brain activity of the C3 and C4 electrodes in any of the conditions. CONCLUSION: While the sample size was low, this exploratory study noted the presence of BLD however the results did not provide evidence of significant limitations in either the EMG or EEG data.

Factores tempranos asociados a apendicectomía negativa / Early factors associated with negative appendectomy

Objetivo: analizar características predictoras de apendicectomía negativa (AN) en una cohorte de pacientes llevados a cirugía durante el año 2018 en una institución de salud de alta complejidad de la ciudad de Medellín, Colombia. Materiales y Métodos: seguimiento retrospectivo a una cohorte basada en registros médicos. Se analizaron pacientes adultos sometidos a apendicectomía. Se estimó la tasa de AN y se describieron características clínicas, paraclínicas y sociodemográficas. Se analizaron predictores de AN mediante el modelo lineal generalizado familia binomial, enlace logarítmico. Se presentan razones de riesgo (RR) observadas y ajustadas junto con intervalos de confianza del 95% (IC95%). Para el modelo multivariado se estimó el área bajo la curva del operador receptor (ROC). Resultados: la tasa de AN fue de 5,2%. No se solicitó tomografía computarizada (TC) de abdomen en el 48,9% de los casos, 4,1% de los pacientes presentaron disuria. Entre los factores estudiados, la disuria, no solicitud de TC, edad y leucocitosis, se asociaron significativamente con mayor riesgo de AN. Resaltan particularmente los pacientes que presentaron disuria y no les fue solicitado TC, en quienes el riesgo ajustado de AN fue de 30,3% (RR = 17,31; IC95% 5,00 ­ 59,87). ROC fue 0,834. Conclusiones: los pacientes llevados a cirugía sin TC y que se presentaron con disuria, particularmente los de mayor edad, concentraron el mayor riesgo de AN. Considerar estas características al definir el manejo quirúrgico del paciente con sospecha de apendicitis aguda, puede contribuir a disminuir las AN..(Au)

Objective: to analyze predictive characteristics of negative appendectomy (NA) in a cohort of patients who underwent surgery during 2018 in a high complexity healthcare institution in the city of Medellín, Colombia. Materials and Methods: retrospective follow-up to a cohort of adult patients who underwent appendectomy. The rate of NA was estimated and the clinical, paraclinical and sociodemographic characteristics were described. The analysis of predictors of NA was carried out using the generalized linear model binomial family, logarithmic link. Observed and adjusted risk ratios (RR) are presented along with 95% confidence intervals (95% CI). For the multivariate model, the area under the receiver operator curve (ROC) was estimated. Results: the NA rate was 5.2%. Abdominal computed tomography (CT) was not requested in 48.9% of the cases, 4.1% of the patients had dysuria. Among the factors studied, dysuria, nonrequest for CT, age and leukocytosis were significantly associated with a higher risk of NA. Is worth noting that the adjusted risk of NA of the patients who presented with dysuria and those in which no CT was requested, was 30.3% (RR = 17.31; 95% CI 5.00 - 59.87). ROC was 0.834. Conclusions: patients who underwent surgery without CT and presented with dysuria, particularly the older ones, had the highest risk of NA. Considering these characteristics when defining the surgical management of patients with suspected acute appendicitis can help reduce NA..(Au)

Attitudes of Medical Students Towards Psychiatry in Venezuela: a 6-Year Longitudinal Study.

OBJECTIVE: The authors evaluated changes in attitude towards psychiatry of medical students in one medical school in Venezuela. METHODS: Balon's modified questionnaire was administered to first and sixth-year medical students to analyze their attitude towards psychiatry. The answers were compared with McNemar's test. RESULTS: The students' negative perception of psychiatry increased by the end of medical school with 45% of sixth-year students reportedly feeling uncomfortable when working with patients with psychiatric illness compared to only 8.3% of first-year medical students. Interest in specializing in psychiatry decreased from 2.6% in first-year medical students to 0% in sixth-year medical students (p=0.001). CONCLUSION: Different factors may lead to the loss of interest in psychiatry of medical students in Venezuela, such as little time spent with patients, being in contact only with patients with psychosis, stigma about psychiatry among medical doctors and friends, feeling more comfortable with other specialties, and other specialties having a higher perceived status and being better paid.