Recovery from aphasia in the first year after stroke.

Most individuals who experience aphasia after a stroke recover to some extent, with the majority of gains taking place in the first year. The nature and time course of this recovery process is only partially understood, especially its dependence on lesion location and extent, which are the most important determinants of outcome. The aim of this study was to provide a comprehensive description of patterns of recovery from aphasia in the first year after stroke. We recruited 334 patients with acute left hemisphere supratentorial ischaemic or haemorrhagic stroke and evaluated their speech and language function within 5 days using the Quick Aphasia Battery (QAB). At this initial time point, 218 patients presented with aphasia. Individuals with aphasia were followed longitudinally, with follow-up evaluations of speech and language at 1 month, 3 months, and 1 year post-stroke, wherever possible. Lesions were manually delineated based on acute clinical MRI or CT imaging. Patients with and without aphasia were divided into 13 groups of individuals with similar, commonly occurring patterns of brain damage. Trajectories of recovery were then investigated as a function of group (i.e. lesion location and extent) and speech/language domain (overall language function, word comprehension, sentence comprehension, word finding, grammatical construction, phonological encoding, speech motor programming, speech motor execution, and reading). We found that aphasia is dynamic, multidimensional, and gradated, with little explanatory role for aphasia subtypes or binary concepts such as fluency. Patients with circumscribed frontal lesions recovered well, consistent with some previous observations. More surprisingly, most patients with larger frontal lesions extending into the parietal or temporal lobes also recovered well, as did patients with relatively circumscribed temporal, temporoparietal, or parietal lesions. Persistent moderate or severe deficits were common only in patients with extensive damage throughout the middle cerebral artery distribution or extensive temporoparietal damage. There were striking differences between speech/language domains in their rates of recovery and relationships to overall language function, suggesting that specific domains differ in the extent to which they are redundantly represented throughout the language network, as opposed to depending on specialized cortical substrates. Our findings have an immediate clinical application in that they will enable clinicians to estimate the likely course of recovery for individual patients, as well as the uncertainty of these predictions, based on acutely observable neurological factors.

Expanding the Conformational Landscape of Minimalistic Tripeptides by Their O-Glycosylation.

We report on the supramolecular self-assembly of tripeptides and their O-glycosylated analogues, in which the carbohydrate moiety is coupled to a central serine or threonine flanked by phenylalanine residues. The substitution of serine with threonine introduces differential side-chain interactions, which results in the formation of aggregates with different morphology. O-glycosylation decreases the aggregation propensity because of rebalancing of the π interactions. The glycopeptides form aggregates with reduced stiffness but increased thermal stability. Our results demonstrate that the designed minimalistic glycopeptides retain critical functional features of glycoproteins and therefore are promising tools for elucidation of molecular mechanisms involved in the glycoprotein interactome. They can also serve as an inspiration for the design of functional glycopeptide-based biomaterials.

The Effects of Cross-Border Transport on Patients With Tibia Fractures.

BACKGROUND: Tibia fractures are common after trauma. Prior studies have shown that delays in treatment are associated with poor outcomes. A subpopulation of our patients are transported from Mexico, adding barriers to prompt care. We hypothesized that patients with tibia fractures crossing from Mexico would have delays in treatment and subsequently worse outcomes. METHODS: The trauma registry of an American College of Surgeons-verified level 1 trauma center was retrospectively reviewed for all tibia fractures admitted from 2010 to 2015. Data collection included demographics, country of injury, characterization of injuries, interventions, complications, and outcomes. Patients were subdivided into those injured in the United States and in Mexico, and the two groups were compared. RESULTS: A total of 498 patients were identified, 440 from the United States and 58 from Mexico. Mexico patients were more severely injured overall, with higher injury severity scores and a higher percentage of patients with abbreviated injury scale scores ≥3 for both head and chest regions. Mexico patients had longer times from injury to admission, as well as increased times to both debridement of open fractures and operative fixation after admission. On subgroup analysis of patients with isolated tibia fractures (other system abbreviated injury scale < 3), times from arrival to treatment and injury severity score were no longer statistically different. CONCLUSIONS: Patients crossing the border from Mexico with tibia fractures have delays in time to admission and from admission to operative management, although this is primarily due to other severe injuries. Ongoing systems development is required to minimize delays in care and optimize outcomes.

The role of mini-bronchoalveolar lavage fluid in the diagnosis of pulmonary tuberculosis in critically ill patients.

BACKGROUND: The detection of Mycobacterium tuberculosis (MTB) in the intensive care unit (ICU) presents several challenges, mainly associated to the clinical state of the patient. The presence of HIV infection further aggravates this scenario, requiring a reliable collection method, with better performance in the microbiological/molecular techniques to be used. We evaluated the performance of two methods for sample collection, mini bronchoalveolar lavage (Mini-BAL) and endotracheal aspirate (ETA), for diagnosis of pulmonary tuberculosis (PTB) in critically ill patients. METHODS: This prospective study involved 26 HIV positive ICU internalized patients, with presumptive PTB who required mechanical ventilation. Two samples were obtained prospectively from 26 HIV ICU patients with presumptive PTB by Mini-BAL and ETA. The samples were processed for smear microscopy, Löwenstein-Jensen medium and the BACTEC Mycobacteria Growth Indicator Tube 960 system®. We define as confirmed PTB patients with positive MTB culture. Furthermore, all samples obtained through the Mini-BAL were analyzed by Xpert® MTB/RIF. RESULTS: Our results demonstrated that the respiratory samples obtained by Mini-BAL were able to increase MTB detection in critically ill patients with presumptive PTB. The Mini-BAL allowed 30% increased recovery and guaranteed enough sample volume for processing in all methods. In addition, the larger volume of the samples obtained with this technique enabled the Xpert® MTB/RIF molecular test for diagnosis of TB. CONCLUSIONS: The Mini-BAL showed be an acceptable alternative to ETA in this population, since these critically ill and often-immunocompromised patients are more likely to develop complications related to invasive procedures.

Research Priorities in Tranexamic Acid After Trauma: Secondary Analysis of the National Trauma Research Action Plan.

INTRODUCTION: Tranexamic Acid (TXA) is an antifibrinolytic drug that is used in traumatic hemorrhage and TBI. Although TXA is considered relatively safe, inexpensive and is widely available, data regarding its mechanisms, optimal dosing, and timing, as well as relative risks and benefits for different patient populations, are inconsistent. In this study we aim to identify and summarize consensus research questions related to TXA across all NTRAP Delphi expert panels to identify priorities for future research on TXA in trauma. METHODS: A secondary analysis was performed using consensus-based research priorities collected by 11 NTRAP topic panels using a Delphi methodology. The database of questions was queried for the keywords "tranexamic" and "TXA". The identified questions were sorted by subject matter and summarized. RESULTS: 7 panels included a total of 73 TXA-related questions. 46 questions reached consensus. The most addressed topic was outcomes (discussed in 64% of questions) followed by indications (49%) and specific patient populations (38%). Due to overlap across panels, questions were summarized and sorted by topic resulting in 21 priority research questions. CONCLUSIONS: 73 total questions and 46 questions reaching consensus were identified by NTRAP panelists. The key topics identified in these questions should be prioritized in future funded research on TXA in trauma. LEVEL OF EVIDENCE: Original Research, IV.

Association of fibrinolysis phenotype with patient outcomes following traumatic brain injury.

BACKGROUND: Impaired coagulation is associated with elevated risk of mortality in trauma patients. Prior studies have demonstrated increased mortality in patients with hyperfibrinolysis (HF) and fibrinolysis shutdown (SD). In addition, prior studies have demonstrated no effect of tranexamic acid (TXA) on fibrinolysis phenotypes. We examined the association of admission fibrinolysis phenotype with traumatic brain injury (TBI) patient outcomes. METHODS: Data were extracted from a placebo-controlled multicenter clinical trial. Patients ≥15 years with TBI (Glasgow Coma Scale score, 3-12) and systolic blood pressure ≥90 mm Hg were randomized in the out-of-hospital setting to receive placebo bolus/placebo infusion (Placebo), 1 gram (g) TXA bolus/1 g TXA infusion (bolus maintenance [BM]); or 2 g TXA bolus/placebo infusion (bolus only [BO]). Fibrinolysis phenotypes on admission were determined by clot lysis at 30 minutes (LY30): SD, ≤0.8%; physiologic, 0.9% to 2.9%; HF, ≥3%. Logistic regression was used to control for age, sex, penetrating injury, Injury Severity Score, maximum head AIS, and TXA treatment group. RESULTS: Seven hundred forty-seven patients met inclusion criteria. Fibrinolysis shutdown was the most common phenotype in all treatment groups and was associated with increased age, Injury Severity Score, and presence of intracranial hemorrhage (ICH). Inpatient mortality was 15.2% for SD and HF, and 10.6% for physiologic ( p = 0.49). No differences in mortality, disability rating scale at 6 months, acute kidney injury, acute respiratory distress syndrome, or multi-organ failure were noted between fibrinolysis phenotypes. CONCLUSION: SD is the most common phenotype expressed in moderate to severe TBI. In TBI, there is no association between fibrinolysis phenotype and mortality or other major complications. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Are Data Driving Our Ambulances? Liberal Use of Tranexamic Acid in the Prehospital Setting.

BACKGROUND: Current data on tranexamic acid (TXA) supports early administration for severe hemorrhagic shock. Administration by EMS has been facilitated by developing protocols and standing orders informed by these data. In this study, patterns of TXA use by EMS agencies serving a large level 1 trauma center were examined. We hypothesized that current widespread TXA use often includes administration outside of data-driven indications. METHODS: The trauma registry at a level 1 trauma center was queried for patients who received TXA. To determine the practice patterns and appropriateness of administration of TXA, patients' physiologic state in the prehospital environment based on EMS records, physiologic state on arrival to hospital, and interventions performed in both settings were examined. Over 20 separately managed EMS systems that administer TXA transport patients to this trauma center, allowing for a broad survey of practices. RESULTS: From 2016 to 2021 1089 patients received TXA, 406 (37.3%) having treatment initiated by EMS services. Of these, the average prehospital systolic blood pressure (SBP) was 108.2 mmHg and initial ED SBP was 107.8 mmHg. Only 58.4% of these patients received blood transfusion after arrival to this trauma center. Compliance with standard indications was low with only 14.6% of administrations meeting any data-driven SBP indication. Similar levels of compliance were seen across high volume EMS services. DISCUSSION: Tranexamic acid use has become common in trauma and has been adopted by many EMS systems. These results indicate TXA in the prehospital setting is over-used as administration is not being limited to indications that have shown benefit in prior data.

Cooling rate uncovers epimer-dependent supramolecular organization of carbohydrate amphiphiles.

We show distinct CH-π interactions and assembly pathways for the amphiphile N-(fluorenylmethoxycarbonyl)-galactosamine and its epimer N-(fluorenylmethoxycarbonyl)-glucosamine. These differences result in the formation of supramolecular nanofibrous systems with opposite chirality. Our results showcase the importance of the carbohydrates structural diversity for their specific biointeractions and the opportunity that their ample interactome offers for synthesis of versatile and tunable supramolecular (bio) materials.

Multifunctional calcium-based nanocarriers for synergistic treatment of triple-negative breast cancer.

Targeted breast cancer therapies hold the potential to improve the efficiency of drug delivery to the pathology site without impacting the viability and function of healthy cells. Herein, we developed multifunctional nanocarriers that target simultaneously several downstream signaling processes in triple negative breast cancer cells. The system comprises pH sensitive CaCO3 nanoparticles (NPs) as carriers of the anticancer drug doxorubicin (DOX). The NPs were coated in a layer-by-layer (LbL) fashion using poly-l-lysine and hyaluronic acid to target receptors overexpressed in breast cancer (e.g. CD44, RHAMM). Spheroids of the triple-negative Hs578T cell line were used as a 3D model to assess the therapeutic potential of this system. Our results showed that the NPs act via a synergistic mechanism that combines Ca2+ overload causing cell calcification and DNA damage by DOX. The LbL coating was crucial for the protection of the healthy cells, i.e. it provides NPs with targeting capacity. The overall data suggests that the LbL-coated NPs loaded with DOX hold great potential for the treatment of breast cancer.

The effects of timing of prehospital tranexamic acid on outcomes after traumatic brain injury: Subanalysis of a randomized controlled trial.

BACKGROUND: Tranexamic acid (TXA) is an antifibrinolytic that has shown some promise in improving outcomes in traumatic brain injury (TBI), but only when given early after injury. We examined the association between timing of prehospital TXA administration and outcomes in patients with moderate to severe TBI. METHODS: Patients enrolled in the multi-institutional, double-blind randomized prehospital TXA for TBI trial with blunt or penetrating injury and suspected TBI (Glasgow Coma Scale score ≤ 12, SBP ≥90) who received either a 2-g TXA bolus or a 1-g bolus plus 1 g 8 hour infusion within 2 hours of injury were analyzed. Outcomes were compared between early administration (<45 minutes from injury) and late administration ≥45 minutes from injury) using a χ 2 , Fischer's exact test, t test, or Mann-Whitney U test as indicated. Logistic regression examined time to drug as an independent variable. A p value less than 0.05 was considered significant. RESULTS: Six hundred forty-nine patients met inclusion criteria (354 early and 259 late). Twenty-eight-day and 6-month mortalities, 6-month Glasgow Outcome Scale-Extended, and disability rating scale scores were not different between early and late administration. Late administration was associated with higher rates of deep venous thrombosis (0.8 vs. 3.4%, p = 0.02), cerebral vasospasm (0% vs. 2%, p = 0.01), as well as prolonged EMS transport and need for a prehospital airway ( p < 0.01). CONCLUSION: In patients with moderate or severe TBI who received TXA within 2 hours of injury, no mortality benefit was observed in those who received treatment within 45 minutes of injury, although lower rates of select complications were seen. These results support protocols that recommend TXA administration within 45 minutes of injury for patients with suspected TBI. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level II.

Efficacy of molecular and nano-therapies on brain tumor models in microfluidic devices.

The three-dimensional (3D) organization of cells affects their mobility, proliferation, and overall response to treatment. Spheroids, organoids, and microfluidic chips are used in cancer research to reproduce in vitro the complex and dynamic malignant microenvironment. Herein, single- and double-channel microfluidic devices are used to mimic the spatial organization of brain tumors and investigate the therapeutic efficacy of molecular and nano anti-cancer agents. Human glioblastoma multiforme (U87-MG) cells were cultured into a Matrigel matrix embedded within the microfluidic devices and exposed to different doses of free docetaxel (DTXL), docetaxel-loaded spherical polymeric nanoparticles (DTXL-SPN), and the aromatic N-glucoside N-(fluorenylmethoxycarbonyl)-glucosamine-6-phosphate (Fmoc-Glc6P). We observed that in the single-channel microfluidic device, brain tumor cells are more susceptible to DTXL treatment as compared to conventional cell monolayers (50-fold lower IC50 values). In the double-channel device, the cytotoxicity of free DTXL and DTXL-SPN is comparable, but significantly lowered as compared to the single-channel configuration. Finally, the administration of 500 µM Fmoc-Glc6P in the double-channel microfluidic device shows a 50 % U87-MG cell survival after only 24 h, and no deleterious effect on human astrocytes over 72 h. Concluding, the proposed microfluidic chips can be used to reproduce the 3D complex spatial arrangement of solid tumors and to assess the anti-cancer efficacy of therapeutic compounds administrated in situ or systemically.

Leukoaraiosis Is Not Associated With Recovery From Aphasia in the First Year After Stroke.

After a stroke, individuals with aphasia often recover to a certain extent over time. This recovery process may be dependent on the health of surviving brain regions. Leukoaraiosis (white matter hyperintensities on MRI reflecting cerebral small vessel disease) is one indication of compromised brain health and is associated with cognitive and motor impairment. Previous studies have suggested that leukoaraiosis may be a clinically relevant predictor of aphasia outcomes and recovery, although findings have been inconsistent. We investigated the relationship between leukoaraiosis and aphasia in the first year after stroke. We recruited 267 patients with acute left hemispheric stroke and coincident fluid attenuated inversion recovery MRI. Patients were evaluated for aphasia within 5 days of stroke, and 174 patients presented with aphasia acutely. Of these, 84 patients were evaluated at ∼3 months post-stroke or later to assess longer-term speech and language outcomes. Multivariable regression models were fit to the data to identify any relationships between leukoaraiosis and initial aphasia severity, extent of recovery, or longer-term aphasia severity. We found that leukoaraiosis was present to varying degrees in 90% of patients. However, leukoaraiosis did not predict initial aphasia severity, aphasia recovery, or longer-term aphasia severity. The lack of any relationship between leukoaraiosis severity and aphasia recovery may reflect the anatomical distribution of cerebral small vessel disease, which is largely medial to the white matter pathways that are critical for speech and language function.

A Model for Sleep Apnea Management in Underserved Patient Populations.

INTRODUCTION: Obstructive sleep apnea (OSA) is a common condition in the United States that is strongly linked to metabolic disease, cardiovascular disease, and increased mortality. Uninsured populations experience sleep health disparities, including delayed recognition, diagnosis, and treatment of OSA due to barriers accessing and affording care. Partnerships between primary care clinics and sleep medicine specialists for sleep apnea management have the potential to increase screening, testing, and treatment among underserved populations. Here, we present an integrated and cost-effective model that is easier to navigate for patients while maintaining high quality care. METHODS: We designed and implemented a specialty sleep clinic at Shade Tree Clinic, Vanderbilt's student-run, free primary care clinic. Patients with signs and symptoms of OSA were identified at primary care appointments and screened using the STOP-BANG questionnaire. Clinic visits took place over telehealth with a medical student and sleep specialist. Patients were diagnosed using a home sleep test, and if indicated, were prescribed and given a CPAP device for treatment. CPAP adherence was monitored using a cloud-based remote monitoring system. RESULTS: From December 2020 through August 2021, we hosted 6 telehealth Sleep Clinics, seeing a total of 28 patients across these visits. We have received a total of 37 referrals and have coordinated sleep evaluations and diagnostic testing for 18 of these patients so far. Prior to initiation of the sleep clinic, there were 17 patients on our primary care panel at Shade Tree with a diagnosis of OSA. These patients were using donated equipment and many had been lost to follow-up or had broken parts. We were able to replace 10 of these patient's CPAP devices and plan to replace the remaining seven. CONCLUSIONS: We have created a model of integrated specialty care that is efficient and cost-effective. This paradigm can be replicated for the many specialties that are typically overlooked and undertreated when working with uninsured patients. As awareness of this sleep medicine program becomes more widespread at Shade Tree Clinic, we anticipate reaching more primary care patients with signs and symptoms of sleep apnea through student education, cost-effective diagnostics, and partnership with sleep specialists.

Prehospital resuscitation.

Traumatic injury is the leading cause of death in young people in the USA. Our knowledge of prehospital resuscitation is constantly evolving and is often informed by research based on military experience. A move toward balanced blood product resuscitation and away from excessive crystalloid use has led to improvements in outcomes for trauma patients. This has been facilitated by new technologies allowing more front-line use of blood products as well as use of tranexamic acid in the prehospital setting. In this article, we review current practices in prehospital resuscitation and the studies that have informed these practices.

Aromatic carbohydrate amphiphile disrupts cancer spheroids and prevents relapse.

Spheroids recapitulate the organization, heterogeneity and microenvironment of solid tumors. Herein, we targeted spatiotemporally the accelerated metabolism of proliferative cells located on the spheroid surface that ensure structure maintenance and/or growth. We demonstrate that phosphorylated carbohydrate amphiphile acts as a potent antimetabolite due to glycolysis inhibition and to in situ formation of supramolecular net around spheroid surface where alkaline phosphatase is overexpressed. The efficiency of the treatment is higher in spheroids as compared to the conventional 2D cultures because of the 2-fold higher expression of glucose transporter 1 (GLUT1). Moreover, treated spheroids do not undergo following relapse.

Inhibiting cancer metabolism by aromatic carbohydrate amphiphiles that act as antagonists of the glucose transporter GLUT1.

We report on aromatic N-glucosides that inhibit selectively the cancer metabolism via two coexistent mechanisms: by initial deprivation of the glucose uptake through competitive binding in the glucose binding pocket of GLUT1 and by formation of a sequestering nanoscale supramolecular network at the cell surface through localized (biocatalytic) self-assembly. We demonstrate that the expression of the cancer associated GLUT1 and alkaline phosphatase are crucial for the effectiveness of this combined approach: cancer cells that overexpress both proteins are prompter to cell death when compared to GLUT1 overexpressing cells. Overall, we showcase that the synergism between physical and biochemical deprivation of cancer metabolism is a powerful approach for development of effective anticancer therapies.

Intensity- and timing-dependent modulation of motion perception with transcranial magnetic stimulation of visual cortex.

Despite the widespread use of transcranial magnetic stimulation (TMS) in research and clinical care, the dose-response relations and neurophysiological correlates of modulatory effects remain relatively unexplored. To fill this gap, we studied modulation of visual processing as a function of TMS parameters. Our approach combined electroencephalography (EEG) with application of single pulse TMS to visual cortex as participants performed a motion perception task. During each participants' first visit, motion coherence thresholds, 64-channel visual evoked potentials (VEPs), and TMS resting motor thresholds (RMT) were measured. In second and third visits, single pulse TMS was delivered at one of two latencies, either 30 ms before the onset of motion or at the onset latency of the N2 VEP component derived from the first session. TMS was delivered at 0%, 80%, 100%, or 120% of RMT over the site of N2 peak activity, or at 120% over vertex. Behavioral results demonstrated a significant main effect of TMS timing on accuracy, with better performance when TMS was applied at the N2-Onset timing versus Pre-Onset, as well as a significant interaction, indicating that 80% intensity produced higher accuracy than other conditions at the N2-Onset. TMS effects on the P3 VEP showed reduced amplitudes in the 80% Pre-Onset condition, an increase for the 120% N2-Onset condition, and monotonic amplitude scaling with stimulation intensity. The N2 component was not affected by TMS. These findings reveal the influence of TMS intensity and timing on visual perception and electrophysiological responses, with optimal facilitation at stimulation intensities below RMT.

Site-Specific Effects of Online rTMS during a Working Memory Task in Healthy Older Adults.

The process of manipulating information within working memory is central to many cognitive functions, but also declines rapidly in old age. Improving this process could markedly enhance the health-span in older adults. The current pre-registered, randomized and placebo-controlled study tested the potential of online repetitive transcranial magnetic stimulation (rTMS) applied at 5 Hz over the left lateral parietal cortex to enhance working memory manipulation in healthy elderly adults. rTMS was applied, while participants performed a delayed-response alphabetization task with two individually titrated levels of difficulty. Coil placement and stimulation amplitude were calculated from fMRI activation maps combined with electric field modeling on an individual-subject basis in order to standardize dosing at the targeted cortical location. Contrary to the a priori hypothesis, active rTMS significantly decreased accuracy relative to sham, and only in the hardest difficulty level. When compared to the results from our previous study, in which rTMS was applied over the left prefrontal cortex, we found equivalent effect sizes but opposite directionality suggesting a site-specific effect of rTMS. These results demonstrate engagement of cortical working memory processing using a novel TMS targeting approach, while also providing prescriptions for future studies seeking to enhance memory through rTMS.

Application of long-interval paired-pulse transcranial magnetic stimulation to motion-sensitive visual cortex does not lead to changes in motion discrimination.

The perception of visual motion is dependent on a set of occipitotemporal regions that are readily accessible to neuromodulation. The current study tested if paired-pulse Transcranial Magnetic Stimulation (ppTMS) could modulate motion perception by stimulating the occipital cortex as participants viewed near-threshold motion dot stimuli. In this sham-controlled study, fifteen subjects completed two sessions. On the first visit, resting motor threshold (RMT) was assessed, and participants performed an adaptive direction discrimination task to determine individual motion sensitivity. During the second visit, subjects performed the task with three difficulty levels as TMS pulses were delivered 150 and 50 ms prior to motion stimulus onset at 120% RMT, under the logic that the cumulative inhibitory effect of these pulses would alter motion sensitivity. ppTMS was delivered at one of two locations: 3 cm dorsal and 5 cm lateral to inion (scalp-based coordinate), or at the site of peak activation for "motion" according to the NeuroSynth fMRI database (meta-analytic coordinate). Sham stimulation was delivered on one-third of trials by tilting the coil 90°. Analyses showed no significant active-versus-sham effects of ppTMS when stimulation was delivered to the meta-analytic (p = 0.15) or scalp-based coordinates (p = 0.17), which were separated by 29 mm on average. Active-versus-sham stimulation differences did not interact with either stimulation location (p = 0.12) or difficulty (p = 0.33). These findings fail to support the hypothesis that long-interval ppTMS recruits inhibitory processes in motion-sensitive cortex but must be considered within the limited parameters used in this design.