Brain abscess - A rare confounding factor for diagnosis of post-traumatic epilepsy after lateral fluid-percussion injury.

OBJECTIVE: To assess the prevalence of brain abscesses as a confounding factor for the diagnosis of post-traumatic epilepsy (PTE) in a rat model of lateral fluid-percussion-induced (FPI) traumatic brain injury (TBI). METHODS: This retrospective study included 583 rats from 3 study cohorts collected over 2009-2022 in a single laboratory. The rats had undergone sham-operation or TBI using lateral FPI. Rats were implanted with epidural and/or intracerebral electrodes for electroencephalogram recordings. Brains were processed for histology to screen for abscess(es). In abscess cases, (a) unfolded cortical maps were constructed to assess the cortical location and area of the abscess, (b) the abscess tissue was Gram stained to determine the presence of gram-positive and gram-negative bacteria, and (c) immunostaining was performed to detect infiltrating neutrophils, T-lymphocytes, and glial cells as tissue biomarkers of inflammation. In vivo and/or ex vivo magnetic resonance images available from a subcohort of animals were reviewed to evaluate the presence of abscesses. Plasma samples available from a subcohort of rats were used for enzyme-linked immunosorbent assays to determine the levels of lipopolysaccharide (LPS) as a circulating biomarker for gram-negative bacteria. RESULTS: Brain abscesses were detected in 2.6% (15/583) of the rats (6 sham, 9 TBI). In histology, brain abscesses were characterized as vascularized encapsulated lesions filled with neutrophils and surrounded by microglia/macrophages and astrocytes. The abscesses were mainly located under the screw electrodes, support screws, or craniectomy. Epilepsy was diagnosed in 60% (9/15) of rats with an abscess (4 sham, 5 TBI). Of these, 67% (6/9) had seizure clusters. The average seizure frequency in abscess cases was 0.436 ± 0.281 seizures/d. Plasma LPS levels were comparable between rats with and without abscesses (p > 0.05). SIGNIFICANCE: Although rare, a brain abscess is a potential confounding factor for epilepsy diagnosis in animal models of structural epilepsies following brain surgery and electrode implantation, particularly if seizures occur in sham-operated experimental controls and/or in clusters.

Chest percussion, a common yet underutilized art.

Dear Editor Long years of respiratory medicine practice lets one develop a clinical instinct which certainly aids in diagnostic acumen...

Intrapulmonary percussive ventilation improves lung function in cystic fibrosis patients chronically colonized with Pseudomonas aeruginosa: a pilot cross-over study.

High levels of shear stress can prevent and disrupt Pseudomonas aeruginosa biofilm formation in vitro. Intrapulmonary percussive ventilation (IPV) could be used to introduce shear stress into the lungs of cystic fibrosis (CF) patients to disrupt biofilms in vivo. We performed a first-of-its-kind pilot clinical study to evaluate short-term IPV therapy at medium (200 bursts per minute, bpm) and high frequency (400 bpm) as compared to autogenic drainage (AD) on lung function and the behavior of P. aeruginosa in the CF lung in four patients who are chronically colonized by P. aeruginosa. A significant difference between the three treatment groups was observed for both the forced expiratory volume in 1 s (FEV1) and the forced vital capacity (FVC) (p < 0.05). More specifically, IPV at high frequency significantly increased FEV1 and FVC compared to AD (p < 0.05) and IPV at medium frequency (p < 0.001). IPV at high frequency enhanced the expression levels of P. aeruginosa planktonic marker genes, which was less pronounced with IPV at medium frequency or AD. In conclusion, IPV at high frequency could potentially alter the behavior of P. aeruginosa in the CF lung and improve lung function. TRIAL REGISTRATION: The trail was retrospectively registered at the ISRCTN registry on 6 June 2013, under trial registration number ISRCTN75391385.

Contraction response to muscle percussion: A reappraisal of the mechanism of this bedside test.

OBJECTIVE: To study whether the contraction evoked by muscle percussion stems from the excitation of the muscle or of the nerve and to discuss the changes of this response in neuromuscular disorders. METHODS: In 30 neurologically healthy patients undergoing surgery (for ear, nose, or throat problems unrelated to the study) under general anesthesia with propofol and sufentanil we measured with an electrogoniometer the maximal dorsiflexion of the ankle evoked by reflex hammer percussion of the tibialis anterior muscle before and under neuromuscular junction blockade with rocuronium bromide. In 3 additional healthy volunteers we searched for F-waves to disclose whether percussion excites axons within the muscle. RESULTS: Responses from 28 neurologically healthy patients (15 women) were analyzed after exclusion of 2 due to technical problems. Mean age (SD) was 28 (9) years. Maximal dorsiflexion of the ankle was not significantly modified by neuromuscular junction blockade (mean difference 0.01 mV [95%CI, -0.07 to 0.08], p=0.879). Muscle percussion evoked F-waves in the 3 healthy volunteers tested. CONCLUSIONS: Maximal contraction response to muscle percussion has a muscular rather than a neural origin. However, percussion also excites axons within the muscle. SIGNIFICANCE: These findings may provide clues to understand the changes observed in neuromuscular disorders.

Automated Rotational Percussion Bed and Bronchoscopy Improves Respiratory Mechanics and Oxygenation in ARDS Patients Supported with Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) has been used to provide "lung rest" through the use of low tidal volume (6 ml/kg) and ultralow tidal volume (<6 ml/kg) ventilation in acute respiratory distress syndrome (ARDS). Low and ultralow tidal volume ventilation can result in low dynamic respiratory compliance and potentially increased retention of airway secretions. We present our experience using automated rotational percussion beds (ARPBs) and bronchoscopy in four ARDS patients to manage increased pulmonary secretions. These beds performed automated side-to-side tilt maneuver and intermittent chest wall percussion. Their use resulted in substantial reduction in peak and plateau pressures in two patients on volume control ventilation, while the driving pressures (inspiratory pressure) to attain the desired tidal volumes in patients on pressure control ventilation also decreased. In addition, mean partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FiO2) ratio (109 pre-ARPB vs. 157 post-ARPB), positive end-expiratory pressure (10 cm H2O vs. 8 cm H2O), and FiO2 (0.88 vs. 0.52) improved after initiation of ARPB. The improvements in the respiratory mechanics and oxygenation helped us to initiate early ECMO weaning. Based on our experience, the use of chest physiotherapy, frequent body repositioning, and bronchoscopy may be helpful in the management of pulmonary secretions in patients supported with ECMO.

Investigation of the effects of chest physiotherapy in different positions on the heart and the respiratory system after coronary artery bypass surgery.

This trial was conducted to investigate the effect of chest physiotherapy in different positions on the heart and the respiratory system after coronary artery bypass surgery. Patients are divided into two groups of 30 patients each in the study. To the patients in the first group (30 patients), percussion-vibration was performed in the 45° supine position, while slightly laterally lying and endotracheal aspiration was performed in the supine position. To the patients in the second group (30 patients), percussion-vibration was performed in the 0° supine position, while slightly laterally lying and endotracheal aspiration was performed in the supine position. The procedures are repeated two times for all patients and their means were taken. The pre- and postapplication values of patients were measured from central venous and arterial catheters and the values of patient monitors were recorded. Comparison of the two groups in terms of respiratory values did not reveal a significant difference, but chest physiotherapy with the head of the bed at 0° was determined to improve cardiac functions. Evaluation of the groups in terms of pre- and postphysiotherapy applications showed a significant increase in mixed venous oxygen saturation in both groups. Chest physiotherapy with the head of the bed elevated to 45° may be recommended in patients who carry a risk of pulmonary complications and who are candidates for chest physiotherapy at an early stage.

A rapid lateral fluid percussion injury rodent model of traumatic brain injury and post-traumatic epilepsy.

Traumatic brain injury is a leading cause of acquired epilepsy. Initially described in 1989, lateral fluid percussion injury (LFPI) has since become the most extensively used and well-characterized rodent traumatic brain injury and post-traumatic epilepsy model. Universal findings, particularly seizures that reliably develop after an initial latent period, are evident across studies from multiple laboratories. However, the LFPI procedure is a two-stage process, requiring initial surgical attachment of a skull fluid cannula and then reanesthesia for delivery of the epidural fluid pressure wave. We now describe a modification of the original technique, termed 'rapid lateral fluid percussion injury' (rLFPI), which allows for a one-stage procedure and thus shorter operating time and reduced anesthesia exposure. Anesthetized male Long-Evans rats were subjected to rLFPI through a length of plastic tubing fitted with a pipette tip cannula with a 4-mm aperture. The cannula opening was positioned over a craniectomy of slightly smaller diameter and exposed dura such that the edges of the cannula fit tightly when pressed to the skull with a micromanipulator. Fluid percussion was then delivered immediately thereafter, in the same surgery session. rLFPI resulted in nonlethal focal cortical injury in all animals. We previously demonstrated that the rLFPI procedure resulted in post-traumatic seizures and regional gliosis, but had not examined other histopathologic elements. Now, we show apoptotic cell death confined to the perilesional cortex and chronic pathologic changes such as ipsilesional ventriculomegaly that are seen in the classic model. We conclude that the rLFPI method is a viable alternative to classic LFPI, and--being a one-stage procedure--has the advantage of shorter experiment turnaround and reduced exposure to anesthetics.

Should chest examination be reinstated in the early diagnosis of chronic obstructive pulmonary disease?

BACKGROUND: Although proven to be associated with bronchial obstruction, chest signs are not listed among cues that should prompt spirometry in the early diagnosis of chronic obstructive pulmonary disease (COPD) in established guidelines. AIMS: We aimed to explore how chest findings add to respiratory symptoms and a history of smoking in the diagnosis of COPD. METHODS: In a cross-sectional study, patients aged 40 years or older, previously diagnosed with either asthma or COPD in primary care, answered questionnaires and underwent physical chest examination and spirometry. RESULTS: Among the 375 patients included, 39.7% had forced expiratory volume in 1 second/forced vital capacity <0.7. Hyperresonance to percussion was the strongest predictor of COPD, with a sensitivity of 20.8, a specificity of 97.8, and likelihood ratio of 9.5. In multivariate logistic regression, where pack-years, shortness of breath, and chest findings were among the explanatory variables, three physical chest findings were independent predictors of COPD. Hyperresonance to percussion yielded the highest odds ratio (OR = 6.7), followed by diminished breath sounds (OR = 5.0), and thirdly wheezes (OR = 2.3). These three chest signs also gave significant diagnostic information when added to shortness of breath and pack-years in receiver operating-characteristic curve analysis. CONCLUSION: We found that chest signs may add to respiratory symptoms and a history of smoking in the diagnosis of COPD, and we conclude that chest signs should be reinstated as cues to early diagnosis of COPD in patients 40 years or older.

A selective adenosine A2A receptor antagonist ameliorated hyperlocomotion in an animal model of lateral fluid percussion brain injury.

Increased concentration of extracellular adenosine after brain injury is supposed to be one of the causes of secondary brain damage. The purpose of the present study is to examine whether or not administration of adenosine A2A receptor antagonist may be efficacious in ameliorating neurological symptoms by blocking secondary brain damage through cascades initiated by adenosine A2a receptor.Mongolian gerbils were divided into four groups: the trauma-medication (T-M), trauma-saline (T-S), sham-medication (S-M), and sham-saline (S-S) groups. Trauma groups received lateral fluid percussion injury. Medication groups received i.p. injection of SCH58261 (selective adenosine A2A receptor antagonist) until the fifth post-injury day. Open-field locomotion test and grabbing test were conducted before and 1, 3, 5, 7, and 9 days after injury.The total distance of movement in the T-S group was significantly greater than in the other three groups at all time points. In the T-M group, administration of SCH58261 significantly blocked hyperlocomotion, which was observed in the T-S group. There was no significant difference in the total distance among the T-M, S-M, and S-S groups. In the grabbing test, grabbing time was significantly increased in the T-S group 3, 5, 7, and 9 days after the operation. SCH58261 also improved grabbing time in the T-M group.Adenosine A2A antagonist successfully suppressed the trauma-induced hyperlocomotion, presumably by blocking secondary brain damage.

Assessment of the primary stability of dental implants in artificial bone using resonance frequency and percussion analyses.

PURPOSE: There is no quantitative gold standard instrumentation to assess the quality of implant osseointegration. The purpose of this exploratory study was to evaluate the response of two devices (one based on resonance frequency analysis, the Osstell device, and another that analyzes the percussion energy response, the Periometer) to assess the primary stability of implants embedded in artificial bone models. MATERIALS AND METHODS: Standard implants were placed into polyurethane blocks of varying densities, and the two mechanical devices were challenged to test the specimen block series. Both analysis of variance and regression analysis were used to examine the output from each device over each series of specimen blocks as well as to directly compare outputs between the two devices. RESULTS: The stability of the implants increased with the foam density for solid block specimens. Linear regression analysis showed significant correlation between the two instruments for testing with monolithic blocks ( r2 = 0.984). Both devices also indicated that a hybrid block with the greatest density at the top provided the best implant stability versus a hybrid block with relatively low density at the top of the block. However, resonance frequency analysis readings seemed to be more dependent on the density of the top layer of the hybrid blocks. CONCLUSION: Osstell and Periometer readings were in good agreement for monolithic blocks, and they were reasonably consistent when blocks of hybrid density were tested.

Increased tenderness in the left third intercostal space in adult patients with myalgic encephalomyelitis: a controlled study.

A clinical sign has not thus far been associated with myalgic encephalo myelitis (ME). The present study involved systematic clinical examination that included inspection, palpation, percussion and auscultation of the thorax of 42 ME patients and 20 age-matched healthy controls while sitting. Left lateral third intercostal space tenderness was noted in 34 (81%) of the patients and in none of the controls, a difference that was highly statistically significant. This finding may be related to changes in lymphatic function and to the descending course of the thoracic duct. Further studies, preferably blinded and combined with appropriate imaging, are required.

Fibromyalgia and Tinel's sign in the foot.

In the physical examination of the patient suspected of having tarsal tunnel syndrome, the podiatric physician relies on Tinel's sign: tapping the posterior tibial nerve in the tarsal tunnel should produce a distally radiating sensation if the nerve is pathologically compressed at this location. The American College of Rheumatology recognizes fibromyalgia as a condition characterized by multiple "tender points" on physical examination. This report compares the locations of the 18 critical diagnostic fibromyalgia points with known sites of anatomical entrapment of peripheral nerves in the lower extremity. We also describe a patient with both fibromyalgia and tarsal tunnel syndrome. Tinel's sign in the lower extremity is a valid technique for assessing peripheral nerve compression in the patient with fibromyalgia.

A saturated-fat diet aggravates the outcome of traumatic brain injury on hippocampal plasticity and cognitive function by reducing brain-derived neurotrophic factor.

We have conducted studies to determine the potential of dietary factors to affect the capacity of the brain to compensate for insult. Rats were fed with a high-fat sucrose (HFS) diet, a popularly consumed diet in industrialized western societies, for 4 weeks before a mild fluid percussion injury (FPI) or sham surgery was performed. FPI impaired spatial learning capacity in the Morris water maze, and these effects were aggravated by previous exposure of the rats to the action of the HFS diet. Learning performance decreased according to levels of brain-derived neurotrophic factor (BDNF) in individual rats, such that rats with the worst learning efficacy showed the lowest levels of BDNF in the hippocampus. BDNF immunohistochemistry localized the decreases in BDNF to the CA3 and dentate gyrus of the hippocampal formation. BDNF has a strong effect on synaptic plasticity via the action of synapsin I and cAMP-response element-binding protein (CREB), therefore, we assessed changes in synapsin I and CREB in conjunction with BDNF. Levels of synapsin I and CREB decreased in relation to decreases in BDNF levels. The combination of FPI and the HFS diet had more dramatic effects on the active state (phosphorylated) of synapsin I and CREB. There were no signs of neurodegeneration in the hippocampus of any rat group assessed with Fluoro-Jade B staining. The results suggest that FPI and diet impose a risk factor to the molecular machinery in charge of maintaining neuronal function under homeostatic and challenging situations.