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INTRODUCTION: Bowel obstruction is one of the most common postoperative complications in pelvic surgery. In most cases, adhesive mechanical ileus of the small bowel is the cause. In procedures such as Hartmann's resection or abdominoperineal rectal resection, it seems that the large wound area on the pelvic walls and pelvic floor and the dead space after the removed rectum with mesorectum contribute to the ileus condition. The aim of this paper was to identify the risk factors for ileus after selected pelvic procedures and to map the possible ways of prevention and treatment of these complications. METHODS: We performed retrospective simple analysis of a set of 98 patients who underwent elective abdominoperineal resection of the rectum, pelvic exenteration or Hartmann's resection for rectal cancer between 2017-2022. Postoperative complications were recorded, especially bowel obstruction, and perineal wound or rectal stump healing complications. In all 9 patients, who needed reoperation, we searched for risk factors for ileus known from the literature. We also described the management of ileus. RESULTS: In the group of 9 patients subjected to detailed analysis, 8 risk factors were most common: male gender, obesity, history of radiotherapy, open surgery, requirement of adhesiolysis in primary surgery, large blood loss, difficult dissection, and impaired healing of the rectal stump/perineum. A total of 8 (88.9%) patients had a combination of 4 or more of the mentioned risk factors. CONCLUSION: Our results confirm the impact of risk factors known from the literature; furthermore, they indicate a connection with the formation of a dead space in the pelvis and with complications of the rectal stump or perineal wound healing. Some of the risk factors cannot be changed, and current preventive measures cannot completely prevent the formation of adhesions. It is therefore advisable to look for other materials and methods that would ideally limit the formation of adhesions and at the same time fill the dead space and thus separate it from the perineal wound.
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Íleus , Obstrução Intestinal , Neoplasias Retais , Humanos , Masculino , Reto/cirurgia , Estudos Retrospectivos , Pelve , Neoplasias Retais/cirurgia , Neoplasias Retais/radioterapia , Complicações Pós-Operatórias/etiologia , Períneo/cirurgia , Íleus/etiologiaRESUMO
Hemobilia is an unusual type of gastrointestinal bleeding most frequently due to iatrogenic injury, trauma, or neoplasia. Acute cholecystitis as a cause of hemobilia is rare. We present the case study of a patient with bleeding from eroded gallbladder mucosa in the setting of severe calculous cholecystitis. The hemorrhagic episode was preceded by acute ERCP due to obstructive icterus with extraction of the calculi, followed by the development of severe acute pancreatitis. These factors initially misled the diagnosis. The bleeding was not hemodynamically important and routine diagnostic methods did not reveal its exact source. Direct choledochoscopy (SpyGlassTM) proved to be helpful in determining the right diagnosis, as it ruled out any injury or tumor in the main bile ducts and considerably supported the assumption of intrabladder bleeding. Surgical revision confirmed the cause, and subsequent cholecystectomy solved the whole problem.
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Colecistite Aguda , Colecistite , Hemobilia , Pancreatite , Humanos , Hemobilia/complicações , Hemobilia/diagnóstico , Doença Aguda , Pancreatite/complicações , Colecistite/complicações , Colecistite/cirurgia , Colecistite Aguda/diagnóstico , Colecistite Aguda/diagnóstico por imagem , Hemorragia Gastrointestinal/etiologiaRESUMO
INTRODUCTION: Enhanced recovery after surgery (ERAS) protocols in colorectal surgery leads to improved quality of care and more efficient resource utilization. Despite these positive outcomes, the penetration of ERAS protocols in the Czech Republic is low. The aim of this study is to present a general methodology for implementing an ERAS protocol in colorectal surgery. METHODS: The methodology is based on the authors' extensive experience in implementing clinical protocols at various institutions in the Czech Republic, as well as published international experiences. This methodology is described in detail and supplemented with data obtained during implementation of an ERAS program at the author's institution. RESULTS: The preparatory phase includes in-depth quality of care audits and preparation of an ERAS protocol. The purpose of the audits is to identify areas of care where standardization or targeted changes in clinical practice are desirable. The implementation phase involves staff training, technical implementation support, protocol dissemination, adherence monitoring, and evaluation of a pilot phase with subsequent protocol adjustments. The evaluation phase involves data collection, maintaining a prospective database, and regular assessments. CONCLUSION: The presented methodology describes the individual steps in the process of implementing a clinical protocol into practice. This text can serve as a manual for implementing an ERAS protocol in colorectal surgery at any institution.
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Cirurgia Colorretal , Procedimentos Cirúrgicos do Sistema Digestório , Humanos , Complicações Pós-Operatórias , Tempo de Internação , Protocolos ClínicosRESUMO
INTRODUCTION: Surgical treatment is the most important part of multimodal management of rectal cancer. In recent years, minimally invasive surgery has been preferred. Minimally invasive procedures include laparoscopy and more recently robotic surgery. Robotic surgery has been developed to eliminate the shortcomings of laparoscopy, especially the parallel position of instruments and their limited movement. The advantages of a robotic system should be most apparent in narrow and deep spaces, i.e. the lesser pelvis. The aim of this study was to analyze the short-term results of robot-assisted surgery for rectal tumors. METHODS: The study is a retrospective analysis of a cohort of 220 patients with robotic-assisted surgery for rectal cancer. The cohort was analyzed in terms of length of surgery, blood loss, number of conversions to open surgery, completeness of TME, distal and circumferential resection margin positivity, length of hospital stays and number of 30-day rehospitalizations. In addition, 30-day postoperative morbidity and mortality were assessed using the Clavien-Dindo score. RESULTS: Robotic-assisted surgeries lasted an average of 184 minutes. In total, 5 operations were converted, i.e. 2.3%. Complete mesorectum was achieved in 90% of the patients. Severe postoperative complications, Clavien-Dindo score 3-4, were observed in 14% of the patients. Anastomotic complications occurred in 9.6% of the patients. The mean length of the hospital stay was 8.4 days. CONCLUSION: Robotic surgery for rectal tumors is a safe method with an acceptable rate of complications. An established training method and a high degree of standardization of the surgical procedures are indisputable advantages of robotic systems, making it possible to achieve very good results in a short time. In terms of perioperative and early postoperative outcomes, robotic surgery outperforms laparoscopic surgery in some parameters.
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Laparoscopia , Neoplasias Retais , Procedimentos Cirúrgicos Robóticos , Humanos , Reto/cirurgia , Procedimentos Cirúrgicos Robóticos/efeitos adversos , Procedimentos Cirúrgicos Robóticos/métodos , Estudos Retrospectivos , Resultado do Tratamento , Neoplasias Retais/cirurgia , Neoplasias Retais/patologia , Laparoscopia/métodos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgiaRESUMO
INTRODUCTION: The aim of this study was to evaluate short-term outcomes of patients undergoing mini-invasive rectal resection within an ERAS (enhanced recovery after surgery) protocol. METHODS: A prospectively managed database of patients undergoing rectal operations performed at our department between January 2015 and April 2020 was retrospectively analyzed. An ERAS protocol was implemented into clinical practice at our department in April 2016 and mini-invasive rectal procedures in May 2016. The ERAS group consisted of all patients who underwent mini-invasive rectal resections or amputations within the ERAS protocol. The control group consisted of patients who underwent open procedures and received standard perioperative care. The extracted data included basic patient characteristics, surgical data, postoperative recovery parameters, 30-day morbidity, length of postoperative stay and 30-day rehospitalization. RESULTS: A total of 110 patients were included in the study: 67 patients in the ERAS group and 43 in the control group. Within the ERAS group 47 patients underwent robotic procedures and 20 had laparoscopic procedures. Patients in the ERAS group had significantly better clinical and laboratory recovery parameters except for postoperative nausea and vomiting. A significantly lower incidence of paralytic ileus (20.9% vs. 3%) and a shorter length of postoperative stay (13 days vs. 9 days) was found in the ERAS group. The rehospitalization rate and 30-day morbidity were not different between the ERAS and control group. CONCLUSIONS: Implementation of the ERAS protocol in combination with mini-invasive approaches leads to better short-term postoperative outcomes after rectal surgery.
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Laparoscopia , Neoplasias Retais , Recuperação Pós-Cirúrgica Melhorada , Humanos , Tempo de Internação , Complicações Pós-Operatórias/epidemiologia , Neoplasias Retais/cirurgia , Reto/cirurgia , Estudos RetrospectivosRESUMO
UNLABELLED: Bouveret syndrome is a gastric outlet obstruction caused by impaction of a gallstone that passes through a cholecystoduodenal or cholecystogastric fistula. It is a rare disease, most common in elderly women with multiple comorbidities and high surgical risk. The diagnosis can be made either radiologically or endoscopically. Endoscopic extraction is the preferred therapeutic option. Surgical intervention is indicated when endoscopic methods fail. We describe a case of Bouveret syndrome in a 79 years old woman. The report is followed by a review of literature on the diagnostics and treatment of this rare syndrome. KEY WORDS: gallstones bilioenteric fistula gallstone ileus duodenal obstruction Bouveret syndrome.
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Fístula Biliar/cirurgia , Obstrução Duodenal/cirurgia , Cálculos Biliares/cirurgia , Obstrução da Saída Gástrica/cirurgia , Fístula Intestinal/cirurgia , Idoso , Fístula Biliar/complicações , Duodenopatias/diagnóstico por imagem , Duodenopatias/etiologia , Duodenopatias/cirurgia , Obstrução Duodenal/diagnóstico por imagem , Obstrução Duodenal/etiologia , Feminino , Cálculos Biliares/complicações , Cálculos Biliares/diagnóstico por imagem , Obstrução da Saída Gástrica/diagnóstico por imagem , Obstrução da Saída Gástrica/etiologia , Humanos , Fístula Intestinal/diagnóstico por imagem , Fístula Intestinal/etiologia , Radiografia , SíndromeRESUMO
UNLABELLED: Perineal hernia is defined as a protrusion of intra-abdominal viscera through a defect in the pelvic floor. Primary hernias are extremely rare; secondary (postoperative) hernias following pelvic surgery, especially abdominoperineal resection or pelvic exenteration, are more common. Impaired perineal wound healing and neoadjuvant chemoradiotherapy in cancer patients are defined as main risk factors. A growing incidence of this complication is expected in connection with an increasing use of laparoscopic approaches and ELAPE. Despite the considerable time since the first described secondary perineal hernia in literature, patient series, prospective studies and treatment guidelines are still missing. The authors present a case of a 66-year-old man with secondary perineal hernia following a previous laparoscopic abdominoperineal resection for rectal cancer undergoing a surgical intervention. This was performed through an abdominal approach using a rectus abdominis muscle flap to repair the pelvic floor defect. KEY WORDS: perineal hernia - hedrocele - RAM - abdominoperineal resection.
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Herniorrafia , Hérnia Incisional/cirurgia , Diafragma da Pelve/cirurgia , Períneo/cirurgia , Neoplasias Retais/cirurgia , Reto do Abdome/transplante , Retalhos Cirúrgicos , Idoso , Humanos , Hérnia Incisional/diagnóstico por imagem , Laparoscopia , Imageamento por Ressonância Magnética , Masculino , Estudos ProspectivosRESUMO
OBJECTIVE: The aim of the paper was to describe the relationship of the anatomical and electrophysiological target for the subthalamic electrode implantation in Parkinson's disease patients defined as the best electrophysiological recordings from multiple paralel electrodes tracts with a target discrepancy explanation. BACKGROUND: Although microrecording is the standard in subthalamic stimulation, microelectrode monitoring prolongs surgical time and may increase the risk of haemorrhagic complications. The main purpose for the electrophysiological mapping is to overcome the discrepancy between the anatomical and electrophysiological targets. METHODS: Subthalamic electrodes were stereotactically implanted in 58 patients using microrecording by means of parallel electrodes at defined distances. The relationship of the final electrode to the anatomical trajectory, the subthalamic nucleus electrical activity length, and the relationship of right and left electrodes were analysed. RESULTS: The final electrode placement matched the anatomical trajectory in 53.4 % of patients on the right side, and 43.1 % of patients on the left side. The electrode position was symmetrical in 38.3 % of patients. The analysis of left and right electrode positions did not prove brain shift as the sole factor responsible for anatomy-functional discrepancy. Further, neither age, Parkinson's disease duration, or L-DOPA adverse effects were confirmed as responsible factors. CONCLUSIONS: The difference between the anatomical trajectory and the final electrode placement underlined the need for functional microelectrode monitoring. Brain shift is not the only causative factor for the difference (Tab. 7, Ref. 27).
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Estimulação Encefálica Profunda/instrumentação , Doença de Parkinson/terapia , Adulto , Idoso , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica , TálamoRESUMO
We studied the appearance of cognitive event-related potentials (ERPs) and event-related de/synchronizations (ERD/S) in the subthalamic nucleus (STN) and globus pallidus internus (GPi). We particularly focused on the rare non-target (distractor) stimuli processing. ERPs and ERD/S in the alpha and beta frequency range were analyzed in seven Parkinson's disease patients and one primary dystonia patient with implanted deep brain stimulation (DBS) electrodes. A visual three-stimulus protocol was used (frequent stimulus, target stimulus, and distractor). The non-target and distractor-related waveforms manifested similar shapes. A specific positive ERP peak around 200 ms and a low alpha frequency ERS were detected from the STN as a response to the distractor stimuli in six of the patients with Parkinson's disease and also in the primary dystonia patient's GPi. This positivity probably reflects an attentional orienting response to the distractor stimuli. The STN and GPi are probably involved in attentional cerebral networks.
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Atenção/fisiologia , Potenciais Evocados/fisiologia , Globo Pálido/fisiologia , Núcleo Subtalâmico/fisiologia , Idoso , Estimulação Encefálica Profunda/instrumentação , Estimulação Encefálica Profunda/métodos , Eletrodos Implantados , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapiaRESUMO
AIMS: Metamorphopsia is important symptom of macular disease. The most common simple detection method of metamorphopsia is Amsler grid. Usually it is used monocularly with best correction for near. Patient should evaluate grid deformation a describe position of the deformity. This method is based on qualitative principle. For quantitative evaluation we can use Software D Chart (Thomson Software Solution). This instrument enables evaluate degree and position of the metamorphopsia in central visual field. Our goal was to establish M-score values in group of young healthy subjects without correction (M-score natural), with cylindrical spectacle lens (M-score SL) and in group of patients with age related degeneration (M-score ARMD). OBJECTS AND METHODS: We had 33 probands divided into 2 samples. The first sample contains 15 young probands with average age 23 years without any eye pathology. The second sample contains 18 patients with ARMD (7 with dry form and 11 with wet form). In our study we used software D Chart (Thomson Software Solution). This software was use in Acer PC with touchable screen. We note total M-score in right eye of all probands. Level for statistic evaluation was set on p = 0.05. RESULTS: Natural M-score values for young probands was: median 0, minimum 0, maximum 2.3. With cylindrical lens we got these values: median 25.2, minimum 3.6, maximum 41.6. In second sample with probands suffer from ARMD we got these values: median 0.8, minimum 0, maximum 29.4. Wilcoxon non-parametric test was used for statistical evaluation. We proved statistically significant difference between all variables. M-score natural vs. M-score SL showed p < 0.001, M-score natural vs. M-score ARMD showed p = 0.04 and M-score SL vs. M-score ARMD showed p < 0.001. CONCLUSION: Our study showed statistically significant differences between variable M-score natural, M-score SL and M-score ARMD. We found that printed Amsler grid as well as its digital modification D Chart are suitable for determining metamorphopsia in central visual field. The main advantage of D Chart is quantitative evaluation of the test with M-score and digital registration of retinal changes during patient´s follow up.
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Oftalmologia , Optometria , Adulto , Humanos , Transtornos da Visão/diagnóstico , Acuidade Visual , Testes de Campo Visual , Adulto JovemRESUMO
Pelvic surgeries such as extirpation of the rectum or pelvic exenteration lead to a creation of a dead space, which can be cause of complication, such as bowel obstruction, perineal hernia, abscess or hematoma. A growing incidence of complication is expected in connection with the increasing use of laparoscopic and robotic approaches or ELAPE method. Since the bone structures do not allow compression, the only way to deal with the dead space is to fill it in. Present methods provide the filling with omental or myofascial flaps. The length and the mobility of the omental flap can be the limitation. Myofascial flaps are technically more demanding and bring the complications of a donor place. Synthetic or biological meshes do not deal with dead space problematic. Modern technologies using nanomaterials offer the possibility to produce a material with specific properties for example shape, inner structure, surface, or time of degradation. The modified material could also satisfy the requirements for filling the dead space after surgeries.
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Pelve/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Reto/cirurgia , Materiais Biocompatíveis , HumanosRESUMO
This work deals with sensitivity and specificity in spectral OCT in detection of early glaucoma. Our goal was to evaluate data from RNFL analysis and compare them with resulted diagnosis of glaucoma neuropathy based on visual field changes. This retrospective study contains 31 subjects who undergone OCT examination in our department between years 2008 and 2017. Test statistic showed RNFL OCT sensitivity 63.64 % and specificity 90 %. Test ROC (receiver operating characteristic curve) showed AUC (area under curve) 0.734, which was statistically significant (p = 0.0097). We found that spectral OCT SLO with RNFL analysis is useful and effective instrument in analysis of glaucoma.
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Glaucoma/diagnóstico por imagem , Fibras Nervosas , Células Ganglionares da Retina , Tomografia de Coerência Óptica , Humanos , Pressão Intraocular , Estudos Retrospectivos , Sensibilidade e Especificidade , Testes de Campo VisualRESUMO
OBJECTIVE: The study was designed to investigate the neurocognitive network in the frontal and lateral temporal cortices that is activated by the complex cognitive visuomotor tasks of letter writing. METHODS: Eight epilepsy surgery candidates with implanted intracerebral depth electrodes performed two tasks involving the writing of single letters. The first task consisted of copying letters. In the second task, the patients were requested to write any other letter. The cognitive load of the second task was increased mainly by larger involvement of the executive functions. The task-related ERD/ERS of the alpha, beta and gamma rhythms was studied. RESULTS: The alpha and beta ERD as the activational correlate of writing of single letters was found in the sensorimotor cortex, anterior cingulate, premotor, parietal cortices, SMA and the temporal pole. The alpha and beta ERD linked to the increased cognitive load was present moreover in the dorsolateral and ventrolateral prefrontal cortex, orbitofrontal cortex and surprisingly also the temporal neocortex. Gamma ERS was detected mostly in the left motor cortex. CONCLUSIONS: Particularly the temporal neocortex was activated by the increased cognitive load. SIGNIFICANCE: The lateral temporal cortex together with frontal areas forms a cognitive network processing executive functions.
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Cognição/fisiologia , Lobo Frontal/fisiologia , Processos Mentais/fisiologia , Rede Nervosa/fisiologia , Desempenho Psicomotor/fisiologia , Lobo Temporal/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Dominância Cerebral/fisiologia , Eletroencefalografia , Feminino , Lobo Frontal/anatomia & histologia , Mãos/inervação , Mãos/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Destreza Motora/fisiologia , Movimento/fisiologia , Neocórtex/anatomia & histologia , Neocórtex/fisiologia , Rede Nervosa/anatomia & histologia , Vias Neurais/fisiologia , Testes Neuropsicológicos , Lobo Temporal/anatomia & histologia , Volição/fisiologia , RedaçãoRESUMO
In order to study cerebral activity related to preparation and execution of movement, evoked and induced brain electrical activities were compared to each other and to fMRI results in voluntary self-paced movements. Also, the event-related desynchronization and synchronization (ERD/ERS) were studied in complex movements with various degrees of cognitive load. The Bereitschaftspotential (BP) and alpha (8-12 Hz) and beta (16-24 Hz) ERD/ERS rhythms in self-paced simple movements were analyzed in 14 epilepsy surgery candidates. In previous studies, the cortical sources of BP were consistently displayed contralateral to the movement in the primary motor cortex and somatosensory cortex, and bilateral in the supplementary motor area (SMA) and in the cingulate cortex. There were also small and inconstant BP generators in the ipsilateral sensorimotor, premotor, and dorsolateral prefrontal cortex. Alpha and beta ERD/ERS were also observed in these cortical regions. The distribution of contacts showing ERD or ERS was larger than of those showing BP. In contrast to BP, ERD, and ERS frequently occurred in the orbitofrontal, lateral and mesial temporal cortices, and inferior parietal lobule. The spatial location of brain activation for self-paced repetitive movements, i.e., writing simple dots, was studied using event-related functional MRI (fMRI) in 10 healthy right-handed subjects. We observed significant activation in regions known to participate in motor control: contralateral to the movement in the primary sensorimotor and supramarginal cortices, the SMA and the underlying cingulate, and, to a lesser extent, the ipsilateral sensorimotor region. When the fMRI was compared with the map of the brain areas electrically active with self-paced movements (intracerebral recordings; Rektor et al., 1994, 1998, 2001b, c; Rektor, 2003), there was an evident overlap of most results. Nevertheless, the electrophysiological studies were more sensitive in uncovering small active areas, i.e., in the premotor and prefrontal cortices. The BP and the event-related hemodynamic changes were displayed in regions known to participate in motor control. The cortical occurrence of oscillatory activities in the alpha-beta range was clearly more widespread. Four epilepsy surgery candidates with implanted depth brain electrodes performed two visuomotor-cognitive tasks with cued complex movements: a simple task--copying randomly presented letters from the monitor; and a more complex task--writing a letter other than that which appears on the monitor. The second task demanded an increased cognitive load, i.e., of executive functions. Alpha and beta ERD/ERS rhythms were evaluated. Similar results for both tasks were found in the majority of the frontal contacts, i.e., in the SMA, anterior cingulate, premotor, and dorsolateral prefrontal cortices. The most frequent observed activity was ERD in the beta rhythm; alpha ERS and ERD were also present. Significant differences between the two tasks appeared in several frontal areas--in the dorsolateral and ventrolateral prefrontal and orbitofrontal cortices (BA 9, 45, 11), and in the temporal neocortex (BA 21). In several contacts localized in these areas, namely in the lateral temporal cortex, there were significant changes only with the complex task--mostly beta ERD. Although the fMRI results fit well with the map of the evoked activity (BP), several discrepant localizations were displayed when the BP was compared with the distribution of the oscillatory activity (ERD-ERS). The BP and hemodynamic changes are closely related to the motor control areas; ERD/ERS represent the broader physiological aspects of motor execution and control. The BP probably reflects regional activation, while the more widespread ERD/ERS may reflect the spread of task-relevant information across relevant areas. In the writing tasks, the spatial distribution of the alpha-beta ERD/ERS in the frontal and lateral temporal cortices was partially task dependent. The ERD/ERS occurred there predominantly in the more complex of the writing tasks. Some sites were only active in the task with the increased demand on executive functions. In the temporal neocortex only, the oscillatory, but not the evoked, activity was recorded in the self-paced movement. The temporal appearance of changes of oscillatory activities in the self-paced movement task as well as in the cued movement task with an increased load of executive functions raises the interesting question of the role of this region in cognitive-movement information processing.
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Cognição/fisiologia , Sincronização Cortical , Córtex Motor/fisiologia , Movimento/fisiologia , Córtex Visual/fisiologia , Adolescente , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Desempenho Psicomotor/fisiologiaRESUMO
The authors give an account of views regarding the use of non-glucose energy sources in parenteral nutrition during the immediate post-load period/serious operations, severe injuries). Attention is devoted to the metabolic pathway of fructose and its disorders. In hereditary fructose intolerance an infusion of D-fructose or D-glucitol (= sorbitol) can induce life threatening hypoglycaemia (unless glucose is administered concurrently). According to some views, in subjects with this intolerance the organism is threatened also by hepatic and renal failure; their development may be independent on hypoglycaemia. Fructose and D-glucitol (sorbitol) therefore should not be administered by the parenteral route. This view is supported by cases where hereditary fructose intolerance could not be revealed from the case-history and clinical manifestations. Some countries have already eliminated fructose and D-glucitol (sorbitol) from their pharmacopoeias.
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Erros Inatos do Metabolismo da Frutose , Frutose/metabolismo , Nutrição Parenteral , Alimentos Formulados/efeitos adversos , Frutose/administração & dosagem , Frutose/efeitos adversos , Erros Inatos do Metabolismo da Frutose/metabolismo , Humanos , Nutrição Parenteral/efeitos adversos , Sorbitol/administração & dosagem , Sorbitol/efeitos adversosRESUMO
Cell volume and its regulation are key factors for cellular integrity and also serve as indicators of various cell pathologies. SPR sensors represent an efficient tool for real-time and label-free observations of changes in cell volume and shape. Here, we extend this concept by employing the use of long-range surface plasmons (LRSP). Due to the enhanced penetration depth of LRSP (~1µm, compared to ~0.4µm of a conventional surface plasmon), the observation of refractive index changes occurring deeper inside the cells is possible. In this work, the responses of a confluent normal rat kidney (NRK) epithelial cell layer to osmotic stress are studied by both conventional and long-range surface plasmons. Experiments are conducted in parallel using cell layers grown and stimulated under the same conditions to enable direct comparison of the results and discrimination of the osmotic stress-induced effects in different parts of the cell.
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Técnicas Biossensoriais/instrumentação , Rim/citologia , Rim/fisiologia , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Linhagem Celular , Tamanho Celular , Sistemas Computacionais , Desenho de Equipamento , Análise de Falha de Equipamento , Pressão Osmótica , Ratos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Coloração e RotulagemRESUMO
OBJECTIVE: The aim of this work was to study the oscillatory changes during target and distractor stimuli processing. We focused mainly on responses after distractor stimuli in the prefrontal cortex and their possible relation to our previous results from the basal ganglia. METHODS: Five epilepsy surgery candidates with implanted depth electrodes performed a three-stimulus paradigm. The frequent stimulus (70%; without required response) was a small blue circle, the target stimulus (15%; with motor response) was a larger blue circle, and the distractor stimulus (15%; without required response) was a checkerboard. The SEEG signals from 404 electrode contacts were analysed using event-related de/synchronization (ERD/S) methodology. RESULTS: The main response to the target stimuli was ERD in the alpha and low beta bands, predominantly in the motor control areas, parietal cortex and hippocampus. The distractor stimuli were generally accompanied by an early theta frequency band power increase most markedly in the prefrontal cortex. CONCLUSIONS: Different ERD/S patterns underline attentional shifting to rare target ("go") and distractor ("no-go") stimuli. SIGNIFICANCE: As an increase in lower frequency band power is considered to be a correlate of active inhibition, the prefrontal structures seem to be essential for inhibition of non-required movements.